Hi. This is my first post!
I have the aforementioned boiler which has been working pretty well for the last 20 years. However, over a period of two days I lost the DHW.
Basically on the Saturday I found that I had to draw more hot water for the DHW to kick in and on the Sunday it stopped completely.
I had a quick look at some of the other post similar. I could see that the Diverter valve was not moving (to the right) to make the micro switches.
If I manually made the micro switch at the Servo Valve the heating kicked in (only did this momentarily to check).
Also noticed that when I checked operation of CH - which worked - the pressure went up from 1bar (normal) to almost 3bar.
Only way I knew to reduce this was through pressure relief vale, PRV.
Has someone out to take a look. Mentioned the pressure issue when CH was on and he opened up something to check for air and water came out. I didn't see this test point. He told me that the CH Expansion vessel was knackered and I'll need a new one - although he did say that wasn't anything to do with my DHW problem - which I had assumed anyway.
He turned on the hot tap in the kitchen to check and nothing came on.
Checked the Diverter valve and this didn't move. He manually pulled it out to the right to make the two micro switches but still nothing. He then called Vaillant tech support who informed him that if that didn't work then could be faulty Diverter and/or micro switches.He said that if when replacing these and it still didn't work could be circuit board (didn't say which one).
With that he quoted me Almost £600 to replace the expansion vessel (which would be fitted externally as per Vaillant Manual, also cheaper option as don't have to remove boiler and will fit under work top in kitchen cupboard), new Diverter valve and two new microswitches. Also quoted me to fit a new boiler around £2500.
He didn't look at servo valve or water section which I read should be an area to look at due to possibility of a split diaphragm.
Also I noticed that the DHW secondary heat exchanger (new type metal one Pt Number 065-034 fitted around 5-6 years ago) had a lot of scale built up around two of the sleeve nuts - looks like there is/was a small leak.
I have taken some photos of the heat exchanger and other parts. My tools are around my brothers at the moment but I want to check the water section as I this looks relatively simple from the manual and a diaphragm I can source for less than £5.
I work as an Automation engineer so I have reasonable technical ability but gas training is limited.
If anyone could suggest a logical testing method I would be extremely grateful i.e. like a flow diagram - does "a" work if "yes" then etc, if "no" then etc,etc.
Don't really have the funds at the moment to fork out so if I can get by until the winter that would be great as I won't be using the CH now its warming up.
I'm assuming I won't need to change the CH expansion vessel if I'm not using the CH? If accidentally turned on where should I release pressure as I'm sure through the PRV is not the best way.
Thanks.
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I have the aforementioned boiler which has been working pretty well for the last 20 years. However, over a period of two days I lost the DHW.
Basically on the Saturday I found that I had to draw more hot water for the DHW to kick in and on the Sunday it stopped completely.
I had a quick look at some of the other post similar. I could see that the Diverter valve was not moving (to the right) to make the micro switches.
If I manually made the micro switch at the Servo Valve the heating kicked in (only did this momentarily to check).
Also noticed that when I checked operation of CH - which worked - the pressure went up from 1bar (normal) to almost 3bar.
Only way I knew to reduce this was through pressure relief vale, PRV.
Has someone out to take a look. Mentioned the pressure issue when CH was on and he opened up something to check for air and water came out. I didn't see this test point. He told me that the CH Expansion vessel was knackered and I'll need a new one - although he did say that wasn't anything to do with my DHW problem - which I had assumed anyway.
He turned on the hot tap in the kitchen to check and nothing came on.
Checked the Diverter valve and this didn't move. He manually pulled it out to the right to make the two micro switches but still nothing. He then called Vaillant tech support who informed him that if that didn't work then could be faulty Diverter and/or micro switches.He said that if when replacing these and it still didn't work could be circuit board (didn't say which one).
With that he quoted me Almost £600 to replace the expansion vessel (which would be fitted externally as per Vaillant Manual, also cheaper option as don't have to remove boiler and will fit under work top in kitchen cupboard), new Diverter valve and two new microswitches. Also quoted me to fit a new boiler around £2500.
He didn't look at servo valve or water section which I read should be an area to look at due to possibility of a split diaphragm.
Also I noticed that the DHW secondary heat exchanger (new type metal one Pt Number 065-034 fitted around 5-6 years ago) had a lot of scale built up around two of the sleeve nuts - looks like there is/was a small leak.
I have taken some photos of the heat exchanger and other parts. My tools are around my brothers at the moment but I want to check the water section as I this looks relatively simple from the manual and a diaphragm I can source for less than £5.
I work as an Automation engineer so I have reasonable technical ability but gas training is limited.
If anyone could suggest a logical testing method I would be extremely grateful i.e. like a flow diagram - does "a" work if "yes" then etc, if "no" then etc,etc.
Don't really have the funds at the moment to fork out so if I can get by until the winter that would be great as I won't be using the CH now its warming up.
I'm assuming I won't need to change the CH expansion vessel if I'm not using the CH? If accidentally turned on where should I release pressure as I'm sure through the PRV is not the best way.
Thanks.
View media item 44344 View media item 44343
View media item 44341 View media item 44342
View media item 44340 View media item 44346
View media item 44345