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Andrew Smith
Andrew Smith, Plumber
Category: Home Improvement
Satisfied Customers: 3629
Experience:  City and Guilds Qualified plumber
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I have a Potterton Promax Combi HE Plus A Range Condensing

Resolved Question:

I have a Potterton Promax Combi HE Plus A Range Condensing Combination Boiler and recently we have had intermittent failures of the system to maintain the required room temperature. We have noticed that the thermostat control is sending a message to the boiler and the boiler is receiving the message because the green light is showing but the boiler is not always firing up. By resetting the temperature required on the thermostat down and then putting it back up the message to light up the boiler has generally resulted in the system coming to life and the heating has restarted. Today we cannot get it to respond this way and by changing the thermostat control down and up, we can see the message is being sent and is being received but now all that is happening is the green light is only coming on for a very short time and is then going off and the boiler is not firing up at all. Everything is fine with regards XXXXX XXXXX
Have you any ideas what is wrong and who we would need to ring to get a solution?

Many thanks in advance,
Graham Fildes, Urmston , Manchester M41 7AN...........
Submitted: 3 years ago.
Category: Home Improvement
Expert:  Andrew Smith replied 3 years ago.

XXXXX XXXXX :

It sounds like the relay is faulty in the receiver if the green receive light is flashing, you will probably have to replace the pair as it is usually cheaper than buying an individual receiver.

XXXXX XXXXX :

Do you need a wire around solution to get your heating working until you get one?

Customer:

Many thanks Andrew but as I am not an electrician/ plumber in any way I will need some expert to do this job. Will it be an electrician I need to solve it for me or a plumber? Are you in any way local to my M41 postcode in Manchester? when you mention the green light flashing, it just flashes the once when it first gets the message then it goes off completely where it should stay on and the boiler then fire up. Thanks for you help so far .. Graham..

Customer:

PS Off for my tea now so will be a short delay responding to any answer you send me, thanks. Graham

XXXXX XXXXX :

If you can take the cover off the receiver I can guide you through it?

Customer:

Hi Andrew, just took the outside cover off but there is another cover beneath that one!! Can I just say that at this moment the thermostat is sending a message and the green light is permanently on indicating it is receiving the message, just the boiler has not fired up. Have reduced thermostat temperature and sending stopped & green light gone off; changed thermostat temperature back up and message sending started again and green light has come on but boiler not fired up!!! Very sorry for the confusing story I've given you.... but it is confusing me....

Customer:

Really appreciate you efforts for me...

Customer:

Hot water still working fine...

Customer:

Andrew, I have to leave you now, any chance we could pick this up tomorrow afternoon/evening? What time would be best for me to continue this tomorrow? Sorry but I was not expecting such service and certainly was not expecting to be carrying out any work myself. I'll pick up your answer tomorrow and will follow any time suggestions from yourself. Once again Many Many thanks. Graham.........

XXXXX XXXXX : No problem, just come back to me when you have monitored this for a short while
Customer:

Hi Andrew, sorry for the delay in getting back to you but have been trying to get a fuller picture for you.... The boiler has started as required both in the evening and the morning for the last couple of days... What I have noticed however is once it has reached the required temperature the boiler has gone off as it should, when the temperature then drops and the thermostat starts to send a message to restart the boiler the message is being sent and the green light is on acknowledging the request but the boiler is not restarting. By adjusting the thermostat required temperature down/up messages stop/restart but usually the boiler does nothing. when I tried this again later in the evening the boiler started up and continued to work until the required temperature was reached. All I can think of is something inside is getting a bit warm and will only allow the boiler to start once it is cooled down a little - does this make sense? Once again sorry for the delay.... Thanks Graham...

XXXXX XXXXX : Ok, let's try again
XXXXX XXXXX : Can you try the transmitter under the boiler to ensure it is getting every command signal?
Customer:

As I said previously Andy I am not a plumber/electrician at all I am now retired and was a computer man when I was working....

Customer:

I am not necessarily looking to solve this over the computer, I am just looking for some help to advise where to guide a prospective plumber/electrician to look...

Customer:

all I can say is the green light is lit up when the thermostat is showing it is sending a message...

Customer:

But the boiler is not always kicking in..

Customer:

when I adjust the temperature down on the thermostat the green light goes off coz no message is being sent..

Customer:

when I change the thermostat temperature up then the light goes on, sometimes the boiler kicks in sometimes it doesn't..

Customer:

generally boiler comes on when it has not been on previously but will not always kick in if it has previously been on...

Customer:

Hence majority of times it is coming on when set to but is not always staying on until the end coz when it reaches the required temperature it goes off and then does not always restart when it should do...

Customer:

Signing off now, will look in tomorrow for any response...... Many many thanks....

XXXXX XXXXX : The way to know for sure is remove the thermostat wiring from the boiler and drop a link wire in between the 2 connections and monitor for 24 hours
Customer:

Hi Andrew, many apologies for the delayed response but I have been away for the weekend and have not had access to my emails. I can confirm we are having to replace both the thermostat which sends the messages and the receiver which was receiving messages but not acting as it should have done by starting the boiler. I ended up having to get an expert out to check it out and he will be fitting the pair once they arrive. Thanks for your answers and if I was more electrically minded I am sure we would have got to the required solution quickly and a site cheaper than the final solution... Thanks again for your EXCELLENT responses...

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