Potterton Puma 80 E

Joined
15 Sep 2006
Messages
114
Reaction score
0
Country
United Kingdom
Hope someone can help me!

I've got the above boiler, which has recently developed a problem. I know it has the most useless PCBs in the world (in the 10 years I've had it, I've replaced 4), but I don't know what might be causing this problem.

When calling for DHW, the hot water is very hot. This is regardless of the temperature I set using the Hot Water Temp dial on the boiler itself, no matter what I set that to, the water is still boiling. Yesterday, the water was so hot getting to the kitchen mixer that I couldn't touch the tap!

I've had a look through the faultfinding diagram in the manual, and the only thing I could find similar suggested disconnecting the Modulator Solenoid GV3. I tried this and the water came out luke warm, so it made a difference. The next thing it suggested is to check resistance of of hot water temperature sensor, which I can't do as I don't have the means. The two possible outcomes then are replace the Hot Water Temperature Sensor, or replace the PCB (again!).

I can get a PCB from http://www.cetltd.com/default.asp?part=151 and fit it myself, but I'd need to get a Corgi guy in to replace the sensor.

Any suggestions over which of these its likely to be?

Incidentally, it also makes a loud rattly/vibrating type noise when it first starts up (for both DHW and CH), kind of like the case is rattling. The engineer who looked at it before couldn't find what was wrong. I've also recently noticed a groan coming from the pipes when it first fires up for DHW.

Thanks

Dave
 
Sponsored Links
I know it has the most useless PCBs in the world (in the 10 years I've had it, I've replaced 4), but I don't know what might be causing this problem.
That one'll be "Potterton"

Have you been using new boards or reconned ones?

V hot hw and rattling often means the pump is on its way out. Do all the rads get hot together and quickly?

To do "work" on a boiler you, as owner, have to be "competent",(undefined!), not Corgi regd. That applies equally to pcb's and sensors.

You could test the sensor with a sub £10 multimeter - once you'd learned to use it.
 
Thanks for the reply, I figured you might be first to respond having been through a search on the site and seen you are considered the man with regard to Pottertons!

I have used a mixture of both brand new and reconditioned boards. Do you think it could be the pump rather than the PCB? Haven't had the heating on to check the rads, but can do over the weekend.

Have done some electronics work many years ago, so wouldn't have too much learning with the multimeter, just didn't want to shell out for one if it was unlikely to be necessary, and I'd have very little future use for it!

Would it be worth just getting an engineer out to fix? Any advantage in going direct to potterton?

Thanks for reply!

Dave
 
Nah, we all know something about Pumas, I'm just stuck at home a lot!

I thought you said you'd run the CH - try it. If the pump's dud the boiler will quickly overheat (bangs - turn it off then). Test by removing central screw (or captive black octagonal knob, probably) from pump and you should feel it turn when boiler's on, if not , turn it to try to free pump.

Any advantage in going direct to potterton?
Well, they would fix it, but for £245.
 
Sponsored Links
ChrisR said:
Nah, we all know something about Pumas, I'm just stuck at home a lot!

I thought you said you'd run the CH - try it. If the pump's dud the boiler will quickly overheat (bangs - turn it off then). Test by removing central screw (or captive black octagonal knob, probably) from pump and you should feel it turn when boiler's on, if not , turn it to try to free pump.

Well, they would fix it, but for £245.


Sorry, noise has been there for a while, last time we had an engineer was Nov, so CH was being used, but he couldn't pinpoint cause of rattling/vibrating. Boiler does not bang though. Although a reconditioned PCB I used caused what the engineer described as an explosive ignition, so we changed that one!

I have a black octagonal plastic cover which plugs onto a knob of some sort on the pump, so that's what I turn?

Will def avoid Potterton direct then!

Dave
 
Unscrew the knob. It's on a bolt head you want it to stay on really.

Could be scale in your heat exchanger, hard to tell from here.

What's the hot water flow with tap wide open, once it's warmed up, in litres/minute?
 
ChrisR said:
Unscrew the knob. It's on a bolt head you want it to stay on really.

Could be scale in your heat exchanger, hard to tell from here.

What's the hot water flow with tap wide open, once it's warmed up, in litres/minute?

Haven't measured in litres/min, and I'm at work so can't check at the moment. There doesn't appear to have been any particular change in flow of the DHW. Literally since Wed, the hot water is just too hot to touch once its warmed up. We're used to it being v hot when the heat is on (if the heating has just come on to warm the rads, and hot water is called, its usually too hot, then cools a bit). When engineer called in Nov, said the boiler was very clean, and each year he's been has said overall clean and in decent nick.

Was looking into changing it, but he said to hang on to it til it dies. However, I'm now selling the house, and as much as I don't want to fork out for reparis, I want to make sure its all working for the new owners.

Cheers

Dave
 
You can buy a cheap yellow DVM for about £6 in places like Maplins and it can diagnose lots of problems roung the house and car!

There are two sensors, you can check both cold and they should be about 13K if I remember correctly but look for similar resistances rather than exact values.

Tony
 
IS that wavydave from UKRM ?

maybe you shoud just phone me at CET, it will certainly be faster than geting into arguments over competence
 
raden said:
IS that wavydave from UKRM ?

maybe you shoud just phone me at CET, it will certainly be faster than geting into arguments over competence

Don't know what UKRM is sorry!

Are you CET that supply the reconditioned PCBs etc?

I was going to call yesterdy for a replacement, but now with this question of whether it could be the pump, I dont' know what's best to proceed.

How can you help out?

Cheers

Dave
 
Am I missing something but how can it be the pump thats not running if the boiler doesnt trip on DHW.
If the waters too hot and the boiler is still firing, if the pump had gone it would have boiled and shut off after about 10 seconds
I would be looking at the DHW thermistor being tested first.
If you have removed the power from the solenoid and the water dropped to luke warm then that means whatever is driving the solenoid is either not sending a signal(sensor)or not being interpreted(pcb).

Stan :idea:
 
Pumas typically don't trip out on hot water if the pump's not running, but they do get it hotter because the water's not circulating so the boiler thinks it's cool, and doesn't modulate down.
They don't have a secondary heat exchanger, so the "main" one has cold tap water cooling it directly.
I think that makes sense.
?
 
pannierstan said:
I would be looking at the DHW thermistor being tested first.

Since thats quick and easy with a meter I agree with that as the first thing to do.

However if the pump is not running then as Chris has deduced the sensor is not in the water circuit and the DHW runs hot. A faulty pump will prevent any CH though.

I think that it MAY be possible for the PCB to forget to run the pump on DHW but still run on CH. Does anyone know if thats possible?

Tony
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top