Potterton Promax 24 HE boiler - Heating without hot water??

[neiljacobs]

Hi, I have a Potterton Promax 24 HE boiler on a pumped system. Since the start of the recent cold weather I have been unable to get the heating on without the hot water being on. Once the water is hot enough the boiler shuts off regardless of whether the heating has reached the desired temperature or not. I have changed the programmer and heating thermostat without any joy. My next step is the control card but don't want to fork out £140+ if this isn't the problem.

 

[bengasman]

Changing the pcb would have as little effect as the money wasted no timer and thermostat.
Some more info on the system would not go amiss.

 

[Agile]

After spending quite a bit already and faced with a significant further cost, dont you think you would have been better getting a competent heating engineer who would identify the fault and repair it?

Tony

 

[Newcastle88]

Hi, I have a Potterton Promax 24 HE boiler on a pumped system. Since the start of the recent cold weather I have been unable to get the heating on without the hot water being on. Once the water is hot enough the boiler shuts off regardless of whether the heating has reached the desired temperature or not. I have changed the programmer and heating thermostat without any joy. My next step is the control card but don't want to fork out £140+ if this isn't the problem.

are you on a Y plan or S plan?

 

[Agile]

Yes, he would be better getting a new motorised valve(s) or just possibly a new motor depending on the make(s) or the actual fault.

Tony

 

[neiljacobs]

Since the weather turned colder a couple of weeks ago we have been unable to have heating without the hot water being on. Once the hot water reaches the desired temperature, the boiler shuts off and the only way to get heating again is to use the hot water up or to manually override the motorised 2 way valve.

I have tested the motorised 2 way valve on another system and it works fine.
I already had a spare programmer originally changed for visual reasons which I swapped back but no change.
I have rung approximately 15 local plumbers and all seem too busy to come out!

Full spec is as follows:

Potterton Promax 24 HE
Heatrae Sadia Megaflow Boiler
22mm Honeywell 2-Port Zone Valve V4043
Danfoss Randall HPA2 2 Port Valve Actuator
Invensys Drayton Lifestyle LP112 24 Hour Digital Dual Channel Programmer

Any pointers would be appreciated.

 

[twgas]

Which mv did you test (CH or HW), and how exactly did you test it?

 

[kevplumb]

if its on a megeflo ain't there a zone valve short on that list

 

[Agile]

I have rung approximately 15 local plumbers and all seem too busy to come out!

There is something wrong there!

There are not that many gas registered engineers in the area and two of them post on here.

I find it very hard to believe that they are ALL too busy!

Did you call British Gas as well?

Tony