ideal Response 120

[stulew]

Hello Gents...
I have to replace the expansion vessel on a Ideal Response 120 which should not be to much of a problem and while I am about it I will replace the PRV as well. My problem is this.. the underside of the boiler is pretty inaccessible and by sqeezing my head under it I can see the PRV but I don't think I can get my spanner up there to release the unions. The PRV is at the rear of the boiler and it looks like it is behind the pump. Has anybody worked on this model before and if so can you give me any tips as to how I can get it undone.
If anybody has a copy of the MI's for this model they can email me I would appreciate it.
Cheers...

 

[Ideal man]

If you phone the manufacturers on 01482 498660 the will if you ask them post you a copy of the book, as for the prv, it is a tight job,just need small hands, if there is no bottom access, drop the pump out, to give you a bit more room

 

[stulew]

Thanks for the quick response Ideal man... I will give the bottom access a go. Can I just ask if you know why the Ideal has such a small expansion vessel.

 

[Ideal man]

8 Litres, just the same as most of the other manufacturers, only just a different shape

 

[stulew]

8 litres.... I must be looking at the wrong bit... Are you talking about the conical shaped vessel?

 

[Ideal man]

No , A large vessel to the right of the combustion chamber, behind the pcb's

 

[stulew]

So what is the small vessel? This releases water when the bicycle tyre valve is pressed! Does this have a diaphramn as well. What I am asking is does this vessel have to be replaced as well?

 

[Ideal man]

If its the small silver vessel on the cold main inlet, just to the right of the fan, then that would be the domestic hot water expansion vessel, which also has a diaphragm in it and is only about the size of a tennis ball, this takes up domestic hot water expansion, and has a much higher pre charge pressure than the central heating expansion vessel(the large red one)Was your problem that the pressure went up to 3 bar on heating and then discharged through the prv, which then will possibly leak all the time?

 

[stulew]

Yes the problem is only showing on the heating, the hot water discharges out through the wall, so the customer then just repressurises the system until it happens again. There is no problem with regards to the Hot Water as far as I know.should there be water in this vessel?

 

[Ideal man]

you need to look at the off load pressure of the c\h exp. vessel the valve is on the top of the vessel, just under the top plate held on by 3 bolts,with the system at 0 bar pressure, the exp vessel should be at about 10 psi
if it is not, and you find it at zero, then it has either gone flat, or it is punctured,if so pump it up, keeping the system pressure at zero, you could remove up to 8 litres of water keeping the pressure at zero, as you will displace the volume in the expansion vessel before you get a build up of air pressure in the balloon. If it goes down again in a few days time, the problem will re occur, but this will get you up and runnig while you get a new vessel, to replace the vessel, you need about 15" space above the boiler, and /or 12" clearance to the right, or if not its boiler off the wall to change the vessel

 

[Ideal man]

signing off now, will look again tomorrow

 

[stulew]

Thanks IdealMan I will have another look tomorrow. But as to the other question should the DHW vessel have water in it or is this faulty as well?

 

[ChrisR]

Both should be dry. Sometimes the biguns have a teaspoon of water, not sure why.
Needn't worry about the small ne if there's a cistern supply on the same pipe. If the pressure goes up the float valve will let a bit of water out.

If the main pv is dud you can add one anywhere convenient, like on top of a kitchen cabinet!

 

[stulew]

Thanks Chris.. I have done that before myself, I think this customer would prefer me to replace the original one as they have this boiler located in a cupboard which they use for storage.
Can I just clarify that the DHW expansion vessel having water in should just be left alone if there is no problem with the hot water. And the Heating Expansion Vessel for this boiler is located behind the PCB's to the right hand side.
If I can convince them to have an external Exp Vess then what is the maximum distance the Tee piece to the vessel should be from the boiler on the return pipe (Is it 1 metre?) and what size should I use. Is 12 litre to big for this boiler???

 

[ChrisR]

Check the plummin inside the boiler. If you find that the HW EV is effectively on the supply pipe, so connected to aforementioned cistern(s) with nothing like a check valve in the way, I don't see a problem.

(I think the order of pipes is a bit odd on that boiler. I once had to change the water pressure switch. Though it looked to be inside the boiler, the (fairly new) boiler isolating valves didn't isolate it!)

Expansion vessels go on the return near the boiler - but mostly because somebody said so somewhere, once. (I reckon!) I've put them in the loft with the boiler in the kitchen. Some boiler manfacturers at least, say it doesn't matter.

At least the boiler has a jig, if you need to take it off the wall. Not that they lined up even when new...