Potterton Suprima 30L Driving me Potty! CH Fault.

[Baldyone]

Hi There,

I have a Suprima 30L, which is approx 3 years old, & was working fine. One month ago it started playing up in the really cold weather.

If you have hot water selected on with CH selected on, no probs, hot water gets very hot & rads get nice & hot too. Problem is, when hot water tank hot gets to temp, boiler cuts out (even when room still below thermostat temp).

If you select CH on only, the boiler tries to fire up, fan runs, but after a minute or two, flashing red light comes on, fan keeps running.

Have had circulation valve & motor replaced by heat team engineers (grudgingly). I have been advised a power flush is required as there is a blockage in the pipework.

I have a good engineer coming tomorrow to diagnose the fault which he believes is either a controller fault or wiring fault as he insists it can't be a blockage (& I believe him).

Has anyone come accross this / got any ideas what the problem could be. If you run the fault diagnosis it suggests a blockage or a flow sensor, but with two heat team engineers telling me it's a blockage I am confused.
Cheers. PJ

 

[gas4you]

Boiler its self won't know whether DHW or CH is calling for heat. The confusing part is that you say the fan keeps spinning when CH only.

I would also want to check the valve head and wiring again.

IF it works perfectly for HW then boiler should be fine for CH.

Is there a flow switch fitted in the pipe work off the top of the boiler?

 

[Agile]

Hi There,

I have a good engineer coming tomorrow to diagnose the fault which he believes is either a controller fault or wiring fault as he insists it can't be a blockage (& I believe him).

Has anyone come accross this / got any ideas what the problem could be. If you run the fault diagnosis it suggests a blockage or a flow sensor, but with two heat team engineers telling me it's a blockage I am confused.
Cheers. PJ

However good your engineer is he cannot diagnose such a fault without being there! Unless he is a clairvoyant that is.

I have never seen a Suprima with a built in fault diagnostic system! Perhaps the Heat Team people dont have their own diagnostic skills?

Tony

 

[Baldyone]

Hi Dave,

I don't believe so, but I'm not at home at the moment.

You wouldn't go for a powerflush then?

PJ

 

[gas4you]

Can't advise that for certain without testing the system water personally.

If CH side was blocked, then pump should still be circulating around the basic circuit via the bypass valve. Would expect boiler to fire up then shut off after 30 - 60 secs as it heated the small volume of system water up.

 

[Baldyone]

Hi Tony,

I didn't give the full story as it would take too long. The engineer who is coming out tomorrow has already been out once.

The fault diagnosis process is the flow chart in the back of the manual. (To assess which lights flash when).

So far heat team have been out three times & each time tell me I need a power flush - hence an independent engr check (who is coming back tomorrow).

Confused, well I am.

PJ

 

[gas4you]

Did heat team take a sample of water? Although this is not always a conclusive test.

 

[Baldyone]

Dave,

Heat team didn't take any water. We've drained the system & refilled. prior to first visit.

PJ

 

[bengasman]

First check should be: what happens when ch only is on, and what when dhw only is on.
If at any way at all the boiler works, it is unlikely to be the boiler.
Check timer, roomstat, wiring, mv.

need for powerflush is very simple to test, bottle of hyperflush in the f&e tank and take a water sample after a week, best when system is fully warm

 

[Baldyone]

Thanks

Power flush has been quoted as approx. £500 so I am trying to avoid.

PJ

 

[bengasman]

Thanks

Power flush has been quoted as approx. £500 so I am trying to avoid.

PJ

Quite reasonable for 22 radiators

 

[Baldyone]

Guys,

Problem solved. Cracked open the bypass valve. CH all okay. It would appear that the return from the boiler was connected into flow - not return (or so I'm told). Good engineer turned out to be excellent. This is in fact a rental property - & tenant thought CH came on okay, but was mostly timed with the hot water - hence confusion. It's a fairly new house - plumber must have made a mistake at install.
Powerflush not required - just 1.5 hours labour.

Thanks for all advice. PJ.