Boiler HELP! Please. Potterton.

[rossyl]

Hey any help/advice would be greatly appreciated.

It's a Combi 28i Potterton.

The problem has not just suddenly occurred, it was initially fine when installed. It started doing this about a year ago then got worse, and now in the past two months has gotten even worse.

It does it with the central heating is off or on. No changes have been made to the system.



Central heating is fine.

Taps.

If the tap is not open at least 70% no hot water will come out.

Sometimes You cannot get hot water and have to run the tap in the bathroom to get hot water out of the other taps in the house.


Shower

You have to run the bathroom tap first.
Putting the shower on (its a simple mixer not thermostatic) will not result in hot water.

The mixer must be on FULL hot. The water is boiling, trying to reduce the heat just slightly will result in the water going ice cold.

If you put the mixer back to full hot it still won't give you hot water. You then have to run the tap again for 30secs to 2mins.

Boiler is 2-3years old.

ANY advice.help appreciated.

Thanks

 

[giblets]

Stupid question maybe but if the problem started about a year ago why did you not get it looked at then rather than wait until it got worse?

 

[Agile]

It may come as a surprise to you that Potterton have made several combi boilers.

Unless you tell us the model we have little chance of telling you what kind of problem you have.

Tony

 

[rossyl]

Combi 28i

Sorry. Hope you are able to help.

Thank you.

 

[ChrisR]

The problem of not firing for hw is usually a simple rubber diaphragm.
The shower prob may be due to a fault in the boiler, or the shower plumbing. Has it always been like that, temp-wise?

 

[rossyl]

nope, it was initially absolutely fine. now its awful. it will go from boiling hot to stone cold if you try and adjust the mixer slightly off the hottest setting.

if the mixer is all the way on hot, then the shower will just send out boiling hot water, try and move the mixer slightly to the colder side and it goes stone cold.

 

[namsag]

Potterton performa 28i i take it.... same as baxi 105 instant

 

[chrishutt]

It sounds like you might have a problem with faulty check valves on the shower valve. You can check this by turning off the hot supply from the combi and then seeing if you can then get cold water out of any of the hot taps, while varying the setting of the shower valve control knob. If you can it will be cold water by-passing the shower valve and passing down the hot supply pipe.

 

[bengasman]

If the hot water supply for the kitchen tap is fine, it is unlikely to be a boiler problem.

 

[rossyl]

thanks guys for the help however, as said before it's not a problem limited to the shower...

Taps
Sometimes you cannot get hot water hot from the taps. You have to go to the bathroom and run the same tap you would for the shower.

So it's like this tap is the "master" tap.

ALSO if you only turn the bathroom tap on a bit and not fully open the water sometimes (70% of the time) will not get hot. You have to turn the tap off, then fully open the tap.

Any other ideas?

 

[rossyl]

anyone shed any light on this?

 

[rossyl]

anyone??

 

[bengasman]

anyone shed any light on this?

Chris is probably right, he usually is, though he may not be complete.
Diverters on these are problem prone. Rubber diaphragms tend to go, and the spindles tend to get covered in limescale and stick. They either need a complete overhaul, or just replace the whole unit

 

[bengasman]

Unless you tell us the model we have little chance of telling you what kind of problem you have.

Tony

but Tony, the real problem is obvious, she has a potterton