HELP NEEDED QUICK

[dmthompson]

Hello Everyone,
We have a 10 year old house with a Potterton Prima 30B boiler in the garage - the problem is that the heating and hot water system isnt working - we have no hot water or central heating.

I have checked that the thermastats are turned up high both on the water tank (Located in cupboard nr bathroom) and the room thermastat (Located in hallway). The pilot light is on but no click or ignition whan ststem turned on.

I have called around and checked out google with varying ideas on what the problem is.
From it being the Gas jet to low pressure.

I would like to try and check if it is low pressure by trying to top up the system - any advice on how to do this - I cant see any top up pipes anywhere.

I dont know if this is related to the problem but a week ago the electric shower in the main bathroom went off and the low pressure light came on (on the shower box) - this seemed to fix its self after I switched the shower on and off.


I have two young boys and cant seem to get anyone to check the system until Monday - if I can check things over first I may be able to fix it and also save a small fortune in the process.

Many thanks in advance.

 

[corgiman]

you probably need a new pcb, if you look at the pilot carefully you will probably see a spark jumping through it

Unless you have an expansion vessel (huge round red thing) its not a sealed system

wont be the burner pressure as the burner aint firing.

 

[The Baker]

First, try checking changing 3amp fuse in three pin plug or fused spur that supplies electrical power to your boiler.

If that checks out OK then it could be that non DIY bits need atention like gas valve, pump etc.

Tim

PS it may help if you can provide symptoms/faults in period prior to system failing.

 

[corgiman]

I done it again this is a perm pilot boiler listen to baker and ignore me

DOH

 

[dmthompson]

Symptoms - well the only thing related or not was the low pressure in the shower. There were no other indicators that something was going to go wrong. The heating was on yetsreday and working fine, it had been on for around 3 hours then just went off - the first we knew about it was when the radiators started to go cold.

 

[corgiman]

the water pressure at your shower as nothing to do with the boiler, have you, like baker said, checked the fuse?

 

[dmthompson]

yep checked the fuse

 

[Gasguru]

Have you checked the overheat thermostat hasn't popped out? - its the litlle cross shaped thing just left of the boiler temperature control.

 

[dmthompson]

I did look at the cross hair thing - small, red looks like its housing is a screw in thing - I did move it a little but it then tripped off the pilot - so reignited the pilot and left the thing alone!

is this meant to happen??

 

[corgiman]

try pressing it

 

[D_Hailsham]

10 year old house with a Potterton Prima 30B boiler in the garage - the problem is that the heating and hot water system isnt working - we have no hot water or central heating.

I would like to try and check if it is low pressure by trying to top up the system

Topping up only applies if you have a sealed system.

How many tanks do you have in your loft? If you have only one (large) then you have a sealed system. But if you have two (large and small) then you have an open vented system and topping up does not apply.

If you have a thermostat on the side of the HW cylinder you should have one or two motorized valves which look like one of these:

or

Normally you will have either two two-port (left pic)valves or one three port (right pic).

What do you have?

Assuming you have one three port (which is more common), the following three tests need to be carried out:

1. HW ON; CH turned OFF at time switch
2. CH ON; HW turned OFF at time switch
3. CH ON; HW turned ON at time switch but the HW thermostat turned down

Test 1: Check if boiler lights when the Cylinder thermostat is turned up and goes off when the stat is turned down.

Test 2 and 3: Check if the boiler turns on/off when the room stat is turned up/down

If you have only one or two two-port valves, post the info and you will get more help.

 

[dmthompson]

pressed it and it just tripped off the pilot - (the cross hair button wasnt sticking out much from the housing). Tried this several times and it still just knocks off the pilot light.

 

[corgiman]

mmm never heard it doing that before

 

[dmthompson]

its a 3 port motorised valve nr the cylinder.
I have tried the tests above and nothing seems to ignite the system. Just on the motorised valve there is a small lever on it "Auto" and manual what should it be on ? - have tried to do the test with it on either but still nothing.

I also wonder why we have an issue with the crosshair button thing tripping off the pilot??

could our problem lie with the on off switch for the heating and water?? its wall mounted with a timer on the Left and two sliding switches on the right one for the water the other for the heating.
Note that the timer part of this hasnt worked for a few months and the heating/water had to be switched on/off manually - i have taken the box off and checked the push on connections - they seem fine -also power going to the cables ok.. I did notice that near the timer (back of box) there is a two wire resistor?? type thing light grey.

 

[dmthompson]

??? - just asking also what check am i to do on the motorised valve? - apart from the checks you told me to do on the thermostats - or is the motorised valve the thing that lets more water into the system??
And yes we have two water tanks in the loft 1lg 1sm - checked both of them and water levels ok.