DIY Forum

 

Ultimate Handyman Ultimate Handyman Ultimate Handyman Ultimate HandymanUltimate Handyman on Pinterest

 

DIY Forum/Home improvement advice forum

 

 

A-Z CONTENTS | DISCLAIMER | DIY VIDEO | HOME | SAFETY FIRST | FORUM RULES

It is currently Tue Nov 21, 2017 10:20 am
Visit Thermo worx


Time zone: Europe/London




 

 


Post new topic Reply to topic  [ 14 posts ] 
Author Message
PostPosted: Fri May 05, 2017 11:38 am 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
Hi, I have a Vaillant ecotec plus 637 system boiler, which serves three zones; central heating, underfloor heating and hot water. This is achieved using a VR 61 mixer module, with each zone having its own 2 port, motorised valve. One of these valves controls the heating of a Vaillant unvented hot water cylinder, which feeds the house under mains pressure.

Late last night I noticed there was no hot water from any taps. I checked the boiler and it was showing an S.53 message, which according to the manual means "Appliance is within the waiting period of the operation block function due to water shortage (VL-RL spread too big)". The water pressure in the boiler was fine.

The supply pipe from the boiler to the unvented cylinder was hot on the boiler side of the 2 port valve, but cold on the cylinder side. This suggested to me that the 2 port valve wasn't opening and allowing the heated water from the boiler to pass into the cylinder. This may also explain the S.53 message as neither the CH or underfloor heating valves were open as no heating was being called for, so the boiler was heating up water and pushing it out, but it wasn't going anywhere!

My first thought was the 2 port valve had failed. I slid the override control arm on the valve (which was very stiff) into the manual open position and immediately the supply pipe on the cylinder side of the valve started to warm up. Around 10 minutes later hot water was restored.

Overnight, I left the valve as it was (open), although I didn't position it in the permanently manual position, if you know what I mean, so it was able to slide back to closed if required.

This morning, the heating was on and hot water was available. I noticed the override control arm of the valve had moved back into its normal (closed) position. I decided to check that the 2 port valve for the hot water was getting the required power signal from the VR 61, so took the front off the VR 61 and tested the terminals with an electricians screwdriver. When touching the switched live feed for the CH and underfloor heating terminals it showed there was power, not surprising as I knew the heating was on and the boiler display was showing the "radiator" and "pump" symbols. However, touching the live feed for the hot water terminal I got nothing. I tried for the next 10 minutes to force the boiler to heat up some water; turned a couple of hot taps on to use some water, turned the CH and underfloor heating thermostats down so heating was not being requested and turned the temperature of the hot water on the boiler to maximum. Nothing I did, not even 10 minutes later, would cause the live hot water terminal to show power had been switched on. Also, the boiler didn't show the hot water symbol e.g. a tap symbol. I guess it may be that the cylinder is keeping the water hot enough not to require heating.

I'm now wondering if maybe the boiler or the VR61 is the cause of the issue and the 2 port valve is okay, but just isn't receiving the switched live signal to cause it to open.

I would appreciate any thoughts/guidance on how to troubleshoot this further.


Share on FacebookShare on TwitterShare on DiggShare on DeliciousShare on Google+
Top
 Profile  
Reply with quote  
PostPosted: Fri May 05, 2017 3:21 pm 
Offline
Senior Member
User avatar

Joined: Wed Nov 14, 2007 10:21 pm
Posts: 7341
Location: Northampton
Has thanked: 293 times
Been thanked: 900 times
Dave is more familiar with that kit than me but are you sure the cylinder stat is turned up enough to call for heat?

_________________
As always help on here is free, however if you think you have saved a decent sum of money why not click the link to find out about the charity we're currently supporting? A couple of quid makes a real difference.

donnas-dream-house-charity-t52110.html


Top
 Profile  
Reply with quote  
PostPosted: Fri May 05, 2017 4:12 pm 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
Hi Razor,

It's interesting you should mention the cylinder stat as I am wondering if it is this that has become faulty and is no longer calling for heat. That would explain why the boiler isn't showing the tap symbol and why the hot water live terminal on the VR 61 doesn't send an "open valve" signal to the motorised valve.

Having said that, I'm not exactly sure how the cylinder stat/boiler communication works. The hot water cylinder doesn't have its own physical temperature control, if I want the hot water to be hotter I have to adjust it using the hot water temperature knob on the boiler. So, this morning I turned the boilers hot water temperature up to max assuming this would result in the cylinder requesting more hot water to be supplied by the boiler to heat it to a higher temperature, but as far as I could tell, this didn't happen.

How does the cylinder thermostat communicate with the boiler? Does the boiler "poll" it on a regular basis to determine the current temperatue and then compare this to the required temperature setting on the boiler? Or does the cylinder thermostat know what the required temperature setting is on the boiler and know when the hot water drops below this, then wakes up the boiler with a call for more hot water?

Thanks.


Top
 Profile  
Reply with quote  
PostPosted: Fri May 05, 2017 4:15 pm 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
I spoke to Vaillant Support this afternoon and they suggested I try a reboot - cut the power to the boiler and all the controls, leave off for a few minutes, then turn back on. This would supposedly resolve any "communication" issues that may have arisen.

I'm not convinced, but as I work in IT and this is a common method of resolving PC issues, I'll give it a try tonight :-)


Top
 Profile  
Reply with quote  
PostPosted: Fri May 05, 2017 8:07 pm 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
On getting home from work and having more time than this morning, I turned up the hot water target temperature on the boiler to max and turned on a couple of hot taps. Hey presto, after about 15 minutes, the boiler kicked into life and displayed symbols indicating that the gas valve was actived, the internal pump was running and the burner was operating. More importantly, it did NOT display the radiator, so it wasn't trying to service a call for heat for the radiators or underfloor heating. At this point I tested the live terminal block for the hot water valve and it was live. I felt the cylinder side of the flow pipe and it was too hot to touch. So, everything appears to be working perfectly, including the 2 port valve.

Obviously, none of this explains why there was no hot water last night, so I still can't explain that situation, which was the first time in 6 years (since the system was installed) that the supply of hot water has been an issue.

Regarding my earlier question about the cylinder thermostat. I took a closer look and can see there is a thin cable running from the cylinder to the boiler. I assume therefore that the boiler regularly checks the reading of the thermostat, which is connected to the end of this cable, and determines when the water temperature has dropped below the target temperatue set on the boiler. There are no controls on the cylinder itself.

I'll monitor the hot water and if it doesn't happen again then that's great, otherwise :dunno:


Top
 Profile  
Reply with quote  
PostPosted: Sat May 06, 2017 8:22 am 
Offline
Senior Member

Joined: Mon Apr 13, 2009 8:03 pm
Posts: 6306
Has thanked: 724 times
Been thanked: 763 times
Have you actually got a cylinder stat?

I thought these would be fitted with the VR10 sensor and all temperature settings are via the boiler control panel.

From what I remember, all communications are via ebus between the VR61 and the boiler.

_________________
Dave

www.drlgas.co.uk


Top
 Profile  
Reply with quote  
PostPosted: Sun May 07, 2017 4:55 pm 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
Hi Dave,

Yes there's definitely a cylinder stat and as the cylinder is a Vaillant Unvented cylinder I would expect the sensor to be a vaillant VR10

Yes, ebus is used from the room thermostats (VRC 430 for the radiators, VR 81 for the underfloor heating).


Top
 Profile  
Reply with quote  
PostPosted: Sun May 07, 2017 5:07 pm 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
It appears the fault has occurred again, but in a slightly different manifestation.

We have been away for the weekend and left my 17 year old at home. On arriving back on Saturday afternoon, the house was cold and the main room thermostat read 18 degrees C, when it should be 20/21. All the radiators were cold, however my 17 year old, who hadn't noticed the house was cold, told me he'd had no problems with the hot water over the weekend.

Checked the boiler and it was showing the "internal pump running" symbol. It was clear there was no hot water getting passed the 2 port valve for the central heating and the valve wasn't receiving a signal to open from the VR 61 as the CH switched live terminal was off. What should have been happening is the radiator symbol should have been showing and hot water should have been pumped around the system to warm up the house to the requested temperature.

Powered off the boiler and then back on and immediately, the radiator symbol came on, along with a flame, pump and gas valve actived symbols. The boiler now appeared to be doing what it should be doing, however, the 2 port CH valve still wasn't open, so no hot water was getting to the radiators. The temperature on the boiler was showing 103 degrees C! I then noticed it was showing the S.53 message again - similar to the one shown when the hot water wasn't being heated due to the HW 2 port valve not being opened. This seems to be a similar pattern.

I manually opened the CH 2 port valve and after a few minutes the radiators started warming up.

Clearly there's an issue, but I'm not sure what is causing this.

Any pointers?

I'm getting a little tired of throwing money at this crap Vaillant system. It's been in for 7 years and so far this year I've had to add an external expansion vessel to cope with a problematic/undersized internal vessel, replace the auto bleed valve on the internal pump as it was leaking, replace the pressure release valve, including the cost of paying heating engineers to troubleshoot the various issues.

Hence, I would at least like to understand what is going wrong this time before paying for an engineer to scratch his head while demanding payment for a problem they haven't got a clue about!


Top
 Profile  
Reply with quote  
PostPosted: Wed May 10, 2017 10:26 am 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
The heating engineer turned up today and during his troubleshooting steps he disconnected the eBus connection from the VR 61. Despite the boiler now having no eBus it continued to cycle and call for heat even though it wasn't required. After a bit of head scratching, he re-connected the eBus cable and everything started to work as it should!
So, it appears the eBus connection was lost, resulting in the boiler not knowing what to do and constantly cycling and heating the hot water. Not sure why this has happened, its the first time in 6 years, so it may be the symptom of another issue, but for now everything appears to be working okay.
I'm not sure why powering down the boiler and the VR 61 wouldn't have had the same effect as disconnecting the eBus cable - maybe the cable was slightly loose!

My communication with Vaillant Support was a waste of time as they offerred no support whatsoever. Very disappointing.



For this message the author milleniumaire has received gratitude : gas4you
Top
 Profile  
Reply with quote  
PostPosted: Wed May 10, 2017 6:40 pm 
Offline
Senior Member

Joined: Mon Apr 13, 2009 8:03 pm
Posts: 6306
Has thanked: 724 times
Been thanked: 763 times
Most likely a dodgy connection from what you have posted

_________________
Dave

www.drlgas.co.uk


Top
 Profile  
Reply with quote  
PostPosted: Sat May 13, 2017 11:14 am 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
It's back! It was too good to be true that the issue was being caused by a dodgy eBus connection. We were woken at 6:00am yesterday morning by a boiler that sounded like it was going to explode! I believe the noise was caused by kettleing due to the boiler constantly heating up the water but not sending it round the CH system. It seems to get itself into a cycling mess.

I disconnected the eBus from the VR 61 and it has calmed down and appears to be working again. Clearly, something is wrong somewhere, possibly an electronic issue; VR 430 thermostat, VR 61 wiring centre or boiler pcb. Back to the heating engineer, but I'm not convinced he has a clue.



For this message the author milleniumaire has received gratitude : sajeel
Top
 Profile  
Reply with quote  
PostPosted: Sun May 14, 2017 11:35 am 
Offline
BANNED

Joined: Tue Mar 21, 2017 7:28 pm
Posts: 62
Has thanked: 160 times
Been thanked: 5 times
milleniumaire wrote:
It's back! It was too good to be true that the issue was being caused by a dodgy eBus connection. We were woken at 6:00am yesterday morning by a boiler that sounded like it was going to explode! I believe the noise was caused by kettleing due to the boiler constantly heating up the water but not sending it round the CH system. It seems to get itself into a cycling mess.

I disconnected the eBus from the VR 61 and it has calmed down and appears to be working again. Clearly, something is wrong somewhere, possibly an electronic issue; VR 430 thermostat, VR 61 wiring centre or boiler pcb. Back to the heating engineer, but I'm not convinced he has a clue.

Get another heating engineer in

Sent from my C6603 using Tapatalk


Top
 Profile  
Reply with quote  
PostPosted: Mon May 22, 2017 9:34 am 
Offline
Newly registered Member

Joined: Wed Nov 14, 2012 7:43 pm
Posts: 27
Has thanked: 1 times
Been thanked: 2 times
Finally figured out what the issue is. It appears that the 2 port motorised valve used for the HW cylinder is sticking. So, despite suggestions to change the weather compensation controller and the wiring centre by Vaillant and the heating engineer, the issue is a simple mechanical fault!

A sticking valve explains the symptoms; the boiler constantly cycles trying to heat up the cylinder, but can't because the valve is closed, even thought the system believes it is open, and because heating the hot water is a priority, it never switches to CH. When I notice the cycling, checking the valve and manually forcing it open resolves the issue within a few minutes.

It looks like the issue is with the components on the actuator head, rather than the valve itself, however its a orkli and I'm struggling to find a replacement head, so may have to replace the whole valve with a more common make e.g. Honeywell.


Top
 Profile  
Reply with quote  
PostPosted: Mon May 22, 2017 10:04 am 
Online
Senior Member

Joined: Fri Jan 20, 2006 5:51 pm
Posts: 7313
Location: Essex
Has thanked: 432 times
Been thanked: 1472 times
Thanks for letting us know how it turned out. I was following this thread with interest as it was an unusual problem. Motorised valves are always a good place to start I say with perfect 20:20 hindsight. :lol:

Glad you got it sorted.

DWD

_________________
Painting with BIN


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 


Similar topics
   

Time zone: Europe/London


Who is online

Users browsing this forum: rpk and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Visit Hilti


 

 

 

News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list
ultimatehandyman privacy policy

Contact

 

Powered by phpBB® Forum Software © phpBB Group

phpBB SEO