Potterton Boiler Low DHW Flow

[Gasguru]

The position of the diverter has nothing to do with the DHW pipework - its a complety seperate circuit. The cold water just runs over a wax stat in the end of the diverter.

 

[Agile]

Did you find a gauze inlet filter near the flow restrictor?

Can anybody remember exactly where it is? And confirm I remember it correctly!

If you are a little clever with water connections you can connect up a hose to intermediate points within the boiler to check the flow rate.

Tony

 

[Daviddf]

Cheers guys, i thought that about the diverter valve, thanks for clearing that up. I think your right Agile i am going to have to rig a bit of pipe up to test where the flow slows down. The problems with breaking into the wax flow limiter manifold is that water goes all over the electrical panel, bloody nuisance. Dave

 

[Daviddf]

Sorry, forgot to mention in last post. No i didn't find gauze in the cold water inlet manifold. If there is one, please let me know where it is and i will check it out. Dave

 

[ChrisR]

I'd bashed out a suggestion that you attach a 1/2" tap connector hose to the tap water connection which comes off the top of the waxy end of the diverter valve. But then thought better of it.
I thnk you'll have to dismantle the wax capsule restrictor. You can leave it out if you want.

 

[Daviddf]

Hi ChrisR, please clarify, dismantle the wax flow restrictor and leave it out?? Do you mean leave it out from testing the circuit or do you mean leave it out all together and remove it from the boiler?? Dave

 

[gazthepottertonengineer]

stop messing about and just replace the heat exchanger as it is very very likely it is this that is scaled up and needs replacing

 

[Daviddf]

gaz, r u serious?? i thought that may be a last resort, replace/clean the valves and tubes and stuff (thats what most of the experts reckon on this forum) and then if nothin else fails replace the heat exchanger. crikey this jobs getting more complicated by the minute.

 

[gazthepottertonengineer]

wot im trying to say is that these heat exchangers are always scaling up and 9 times out of 10 you end up replacing it so you might as well stop messing about and repalce it only takes an hour if your quick

 

[Gasguru]

Original post indicates the problem has only just occured - I have yet to change a Puma heat exchanger due to scaling (and most of these boilers are >9 years old).

 

[ChrisR]

You can take out the wax restrictor - but shouldn't be any need.

If you're taking things apart it wouldn't be diff to get some flow through the h/e with citric acid without taking it out. You could do the whole water way in fact. One guy (Dan R) does it with a slightly modifiied garden spray unit. You can sometimes use the washing machine hoses.

Haven't heard of one clogging up in London - which is around medium hardness, but Breezer's did for instance. If the flow rate goes low for any reason such that the tap water goes over 60 odd then the temporary hardness would start to precipitate out like in a kettle.