Hot Water issue - Potterton Puma 80e

[eddieed]

Thanks

Normally I would leave them alone, I did the last, but I don't trust them. I certainly won't let him shut the door like the last one did, but will sit in the kitchen which is the next room to where the boiler is so I can keep an ear out on what he is doing.

 

[Gasguru]

Any decent engineer shouldn't mind you watching, I often engage the customer to try and understand their system better....it helps when they next call me with a problem. Given the poor diagnosis so far you need to see what's going on.

 

[Mike4]

So I am going to ask him to check the following tomorrow:

Blocked Filter on water inlet
Jammed hot start device
Cold inlet isolating valve - Check / remove the flow isolater pressed in the end as can block
Water saving valve
DHW Thermostat / Flow limiter not opening - MOST LIKELY

Having had a scan through the manual I can only see two components capable of limiting the water flow (apart from scale in the heat exchanger, which we have discounted due to the water softener).

1) The adjustable flow limiter (or DHW manual flow limiter - the manual appears to use both terms for the same device) part number 929670
2) The flow restrictor - part number not listed in the MI as far as I can see

I can't see what a 'hot start device' is. Can anyone point out the part number for me please? Same comment for the "DHW thermostat/flow limiter". I can't see this mentioned in the manual. I think it must be the flow restrictor. People use different terms for the same things!

The 'water saving valve' appears to only be fitted to the permanent pilot version, not the OP's Puma is electronic ignition version.

So I think the Npower bod tomorrow only needs requesting to dismantle and clean the adjustable flow limiter (and filter if fitted) and to remove the flow restrictor (if fitted).

Mike

(AKA Mike the Boilerman, for those who haven't sussed me!)

 

[eddieed]

Thanks Mike will let you know how we get on.

 

[Joe4542]

Mike, the hot start device/water saving valve/DHW thermostat/flow limiter would all relate to the same waxstat controlled valve on the DHW outlet (10/19849).

The other flow limiter/restrictor mentioned is the fixed oriface type stuck into the cold ISO valve.

 

[St0rmer66]

All Puma's have the wax capsule diverter on them. Very common to go wrong now that these boilers are getting on a bit! Would be my first guess for the problem described (after checking the flow limiter).

 

[eddieed]

So this guy seems to know what he is doing which is a breath of fresh air.

He has checked the inlet and that is all fine and the plastic bit had already been taken out anyway.

He has removed part 929670 and that looks to be fine as well.

He is now just phoning Potterton about the wax diverter valve to see if that is the culprit as he would need to order that part in to be replaced to see if it fixes the problem.

Will update you all later, thanks again for the help.

 

[eddieed]

Slight edit so part 929670 is going to be order as well as a DHW flow switch these will be fitted when they come in.

Hopefully this may fix it...let's see, probably Monday now.

 

[Gasguru]

The wax element flow limiter is now part no. 10/19849

 

[eddieed]

The wax element flow limiter is now part no. 10/19849

Yes - this is what has been ordered. Apparently they use PlumbCentre for parts. We are booked in for the part fitting on Monday morning.

If it isn't this then it looks like it will be the heat exchanger and thats the point at which I have to call someone else to replace it as they can't as the part is unavailable. I'll get one off ebay and then get it fitted.

The main thing now though is I know that they have checked all other possibilities. They hadn't before.

 

[Agile]

Hasn't anyone measured the flow rate through the boiler!

Tony

 

[Gasguru]

Be aware that some of the ebay heat exchangers have been dropped! Carefully look at the pipes....they get severely bent...often by delivery couriers and there's little chance of straightening them up again.

 

[eddieed]

Hasn't anyone measured the flow rate through the boiler!

Tony

I had said previously that the hot water is coming out at 4 litres a minute is this what you meant. It is significantly less than the cold water flow!

 

[Agile]

OK that's what I meant.

Its too close to the intended 3.5 li/min that the hot start device is intended to give to be meaningful. I am not sure I remember the 3.5 correctly either as its not usually important.

But it does mean that it could well be that part though.

Just remembered that I have a used one in stock too.

Tony

 

[eddieed]

I have just done a more accurate test and it's more like 3.2l a minute.

Does this indicate a problem with the hot start device and what's the part number for this.

Thanks