Combi DHW Problem

[Starboard 10]

Hello to everyone, I've just been given a link to this board from a member of Modshack, looks like a very useful place to be a member of and hopefully I will be able to muck in and share some of my little knowledge with you.

I've got a Halstead Quattro Gold combi an it has developed a niggly fault. The CH side of the system works fine, the problem is with the DHW. When I run a hot tap, sometimes it runs hot and at other times cold, if I tap the side of the boiler an electrical 'click' is heard and it fires up and heats the water, sometimes for a couple of minutes and sometimes long enough for a bath/shower.

Whilst the water is running hot, if a tap/cistern/washing machine is used in another part of the house then the DHW turns cold again, also if the CH is in use the DHW will not heat at all, turning off the CH and clouting the boiler gets the DHW running hot again.

I've ruled out the thermistors by by-passing them and the diaphram in the diverter valve is in good condition. Someone has suggested that the air pressure sensor may be faulty, I cleaned inside the hoses and fan casing probe and it did seen to sort the problem for a couple of days, although I think that this was a fluke as if this was the problem then it is unlikely that the CH would work properly.

If the sensor is suspect, there is an adjuster screw on it, clockwise = + and anti = -, if it needs adjusting should I advance or ****** the screw?

And if I am barking completely up the wrong tree, what could be causing the problem?

For some reason I keep erring on the problem being with the diverter valve, I have replaced the diaphram a few times (very hard water area) and I keep thinking that I may have re-assembled the spindle assembly wrongly, but I don't think this is reallythe case.

Also the microswitch on top of the DV appears to work fine when I activate it with a pencil.

Any ideas would be very welcome.

Thanks!

Stbd 10

 

[croydoncorgi]

You are delving into areas where you clearly are not knowledgeable. The air pressure switch is NOTHING to do with the problem you have and MUST NOT be adjusted. It's a SAFETY device!!! The thermisters are also nothing to do with it. There is NO POINT fiddling with everything in sight - you're breaking the law by interfering with a gas appliance when you are not a 'competent person'. By doing so, you will also invalidate your house insurance.

If the boiler fires OK on CH, the problem must be something to do with the sensor that detects hot water demand or with the diverter valve.

 

[ChrisR]

Watch the diverter when you do your clouting, to see if it's sticking.
If it is you can overhaul it, - if you reassembled it wrongly it wouldn't work at all. New ones from Halstead are someting like £150 + vat but you can get them for far less.

But I think its more likely that there are some bad joints on the pcb or elsewhere. I'd be wiggling connectors - carefully cos its all mains voltage.

The secondary heat exchanger will be scaling up if your water's v hard, but you can descale it of course.

 

[Starboard 10]

You are delving into areas where you clearly are not knowledgeable. The air pressure switch is NOTHING to do with the problem you have and MUST NOT be adjusted. It's a SAFETY device!!! The thermisters are also nothing to do with it. There is NO POINT fiddling with everything in sight - you're breaking the law by interfering with a gas appliance when you are not a 'competent person'. By doing so, you will also invalidate your house insurance.

Yawn, I installed the system and commisioned the boiler myself 10 years ago, also ripped out the cast gas pipework throughout the house and replaced it with copper, installed the gas cooker and both gas fires around the same time and I am still alive with an intact house. Incompetent?, I think not!

If the boiler fires OK on CH, the problem must be something to do with the sensor that detects hot water demand or with the diverter valve.

I have already proved the sensor so that focuses me on the DV, which I suspected all along, thanks!

Watch the diverter when you do your clouting, to see if it's sticking.
If it is you can overhaul it, - if you reassembled it wrongly it wouldn't work at all. New ones from Halstead are someting like £150 + vat but you can get them for far less.

But I think its more likely that there are some bad joints on the pcb or elsewhere. I'd be wiggling connectors - carefully cos its all mains voltage.

The secondary heat exchanger will be scaling up if your water's v hard, but you can descale it of course.

Thanks for the informative reply, I have re-flowed all of the joints on the pcb and proved them with a meter, it's time to strip the DV down and check for wear on the riser components I think, it seems to stop around 0.5mm short of full depression of the microswitch.

Stbd 10

 

[ChrisR]

I certainly wouldn't advise you do anything with gas, you won't know how to test for leaks even if you have the kit to do it. And you'll probably have used unsuitable materials, got pipe sizes wrong etc etc.

You might choose to cross roads without looking. Just because you're still alive doesn't make it a safe practise.

You haven't understood how your diverter works either. There's nothing to wear which would stop the pin extending to the microswitch properly. It's probably dirt /scale/gunge. I suggest you buy a new one - they're only £30 or so.

 

[croydoncorgi]

Yawn

You may well have installed the boiler 10 years ago. But you don't appear to have learned much then or since about how it works!

Otherwise you'd know that the setting of the APS depends on the power of the fan, flue design, venturi type and size, and several other design factors determined by the manufacturer. It is not intended to be adjusted and it's not practical with the boiler installed anyway. How would you find out (for example) what volume of air and combustion products was going through the flue? Write on one side of the paper only and (clue) you can't use operation of a (wrongly adjusted) APS to help you guess.

 

[Starboard 10]

Yawn

You may well have installed the boiler 10 years ago. But you don't appear to have learned much then or since about how it works!

Otherwise you'd know that the setting of the APS depends on the power of the fan, flue design, venturi type and size, and several other design factors determined by the manufacturer. It is not intended to be adjusted and it's not practical with the boiler installed anyway. How would you find out (for example) what volume of air and combustion products was going through the flue? Write on one side of the paper only and (clue) you can't use operation of a (wrongly adjusted) APS to help you guess.

I personally never suspected the APS, the CH works fine so it is quite obvious that the unit is functioning correctly, the suggestion that it may be faulty came from a CORGI engineer who also said that adjustment rather than replacement may sort the problem, LOL.

I posted on this board in the hope of receiving constructive assistance, rather than to be a piggy in the middle of a game between two 'CORGI's'!!!

ROTFLMAO

Stbd 10

 

[Starboard 10]

Finally sorted the problem, removed and stripped down the DV and all was in order and I was now totally stumped. Re-flowed all solder joints on the control pcb again and still no joy.

While I was thinking of my next move I started wiggling wires around the boiler at random, not really expecting anything from it when low and behold, when I touched the wires leading to the gang plug on the multi-functional gas valve it fired up, touched the wires again and it shut down!

I then simply removed the gang plug and sprayed the terminals with electrical contact cleaner, re-instated the plug and all is well, after all the grief it turned out to be a simple contact problem.

Stbd 10

 

[ChrisR]

SOme people just don't want to be helped. You were advised on what to do 4 days ago, and you just got round to it, by accident it seems. Does

"But I think its more likely that there are some bad joints on the pcb or elsewhere. I'd be wiggling connectors "

ring any bells?

There is no "game between corgi's" going on here, just a fight between you and your ego.

 

[oilman]

You were advised on what to do 4 days ago, and you just got round to it, by accident it seems.

Not much different to professionals then. Contact/connection problems are often found by accident and just being observant enough to notice when something happens, and what you did just before. After all, if it's working you can't find it, and if it's not you start looking around. If it's permanently dead it's much easier to find as the goal posts don't keep moving.

 

[PEDANTICVINDICTIVEMAN]

Nothing worse than some DIY idiot thinking he knows it all because he can run a bit of pipework.

I will keep my eyes on the Deaths column in the papers as it's only a matter of time, Yaaaaaaawwwwwwwwwwwwnnnnnnnn.

 

[Bahco]

ROTFLMAO


What is above

 

[Starboard 10]

SOme people just don't want to be helped. You were advised on what to do 4 days ago, and you just got round to it, by accident it seems. Does

"But I think its more likely that there are some bad joints on the pcb or elsewhere. I'd be wiggling connectors "

ring any bells?

Yes it rings a bell and if you brush up on your reading skills you will see that I re-flowed the solder joints on the pcb twice, I also took your advice on wiggling connectors but it made no difference at that time!

There is no "game between corgi's" going on here, just a fight between you and your ego.

If that was my problem I would have been too proud to post about my problem in the first place, I think that the ego problems on this board are related to the CORGI's who cannot accept that many 'lesser' people are often equally as competent, and sometimes more than!

Not much different to professionals then. Contact/connection problems are often found by accident and just being observant enough to notice when something happens, and what you did just before. After all, if it's working you can't find it, and if it's not you start looking around. If it's permanently dead it's much easier to find as the goal posts don't keep moving.

Thank you for that, that describes the scenario exactly!

Any fool can sit behind a keyboard and give vague answers to problems and look down on those they consider to be subordinates, but put those wise men in a hands on situation and then smile as they are reduced from Einstein wannabe's to humble fumblers!

This is supposed to a help forum, not a teacher/naughty schoolboy reform centre, those who may be able to offer help would get more respect doing just that, instead trying to redicule those who post problems.

Nothing worse than some DIY idiot thinking he knows it all because he can run a bit of pipework.

I will keep my eyes on the Deaths column in the papers as it's only a matter of time, Yaaaaaaawwwwwwwwwwwwnnnnnnnn.

You really shouldn't run yourself down in this way, no matter what others say of you, keep your chin up m8!

BTW your username is very appropriate!

ROTFLMAO


What is above

Yup I agree!, some of these CORGI's are certainly good for a laugh if nothing else!

Stbd 10

 

[blahblah]

Green10. I would have some sympathy for you but somehow you've managed to upset a least two of the most helpful, understanding and knowledgable pros that post here.
ROTFLMAO? Any relation to SNAFU or FUBAR?

 

[PEDANTICVINDICTIVEMAN]

Why do you think I have this screename
anyway glad to see your still alive but it wont last.
I dont pretend that I know everthing even though I have done everything in my 33 years in the trade, and just like any other proffesion I get caught out now and again, however there is nothing more dangerous than a diyer who thinks he's being clever.
Make sure you notify your house insurer as they tend not to pay out if they find out your gas work isn't carried out by a reg installer.