Potterton 28i Boiler No Hot Water and Heating

[MaccaTVR]

Hi all,
Hoping for some pointers.

My potterton performa 28i boiler originally hasn't been giving me hot water since around Feb time. I only use hot water from the boiler in my house for doing the dishes so have been using the kettle, but with winter coming up and things it's best I get the thing fixed, and here's the story of what's what so far.

Back in feb, turning on a hot water tap would start giving me warning flashing LEDs. Usually it was the red light for fault on hot water sensor, however sometimes it was just the green flashing led above the symbol for hot water. I'd also like to add that if I kept the water running and also turning on and off a few other taps in the house it would eventually kick in and give me hot water but it finally gave up.

I replaced the hot water sensor and the red flashing led disappeared but still no hot water and all I get now is the green led when I turn on a tap.

That's as far as I got with the water. As I've no need for hot water really and no need for the heating to be on through the summer, the boiler has been turned off completely for a few months.

Turned it back on the other day and now the heating no longer works, which did work completely fine before!

I go and put up the temp on the thermostat (which has power because it's LEDs work) but it's like the boiler doesn't know I want the heating on - the green led on the boiler doesn't come on like it used to before.

The boiler itself does turn on and does fire up and get up to temperature no problem, pressure looks good as well - just no hot water or heating!

I'm pretty handy with tools and general repairs so feel pretty confident in fixing the problem, I just need some help to know what the problems are!

Thanks!

 

[picasso]

Hot water diaphragm knackered and sounds like the diverter valve may be stuck on hot water mode.

 

[MaccaTVR]

Diaphragm repair kit pretty cheap and simple.

As for the diverter valve is there anyway to check if it's the valve itself or the actuator that's at fault? Replacement or could it be repaired?

 

[picasso]

If the boiler is not responding to the thermostat might be worth checking that first before anything else.

 

[MaccaTVR]

Best way to check that?

I know that the thermostat responds to the boiler if that makes sense...

When I turn the power switch to the water only position the LEDs on the thermostat go off.

Turn it to heating and water the LEDs light up. Adjusting the thermostat temp up and down it will change between below and reached

 

[picasso]

Are you talking about a separate room stat or the stat on the front of the boiler?

 

[MaccaTVR]

The separate room one

 

[picasso]

RF or hard wired ?

 

[MaccaTVR]

I'm honestly not too sure... It's a potterton prt2

 

[picasso]

Ok so have you made sure the boiler stat for central heating is turned up and you don't have it set on summer setting? if so you need to link out the stat to rule it out as the problem,

here is a diagram for your boiler showing the link in place across 1 and 2, obviously you need to isolate all the electrics before opening the cover.

 

[MaccaTVR]

Hi sorry for late reply.

Little update.

I have replaced the hot water diaphragm and the diverter valve.

Hot water is working perfectly.

Heating is still exactly the same.

As far as you mentioned about testing the external termostat, I apologise as I'm a little confused as to how you mean to check this?

Are you saying to connect 1 and 2 directly?

 

[picasso]

Yes connect 1 and 2 directly but you MUST isolate the boiler electricity supply before doing so.

 

[MaccaTVR]

Ok, just used some spare wire and hooked 1 and 2 directly.

Power to the external thermostat went off (which I assume would happen) but heating still wouldn't start up.

So I guess that rules out the ext thermostat.

Diverter valve replaced as said, anything else I could check?

 

[picasso]

check the spindle hasn't broken on the central heating control knob.

 

[MaccaTVR]

Spindle looks good, nothing appears broken on either side of the knob