Combi Boiler causing me to pull hair out

[curtis]

Hi

I'm going to tell a story of what appears to be a well troden path but I'm still stumped and suffering with a heating/hot system that is driving me mad even with the advice that the helpful people from Ariston and people from here have suggested.

The Ariston SX20 Combi boiler I have in my flat has been playing up for about 3 weeks now with the following sequence of events.

1. Wake up one morning and the pressure gague is on 0. I top the boiler up and think nothing more of it.

2. The gague is on 0 when I return home from work. Talk to Ariston and they suggest PRV.

3. PRV changed. Short lived success as I notice water appearing from the washing machine connections.

4. Connections fixed with new washers. Fill boiler, short lived success.

5. Ariston suggest that expansion tank may need topping. Done, with short lived success.

6. Leak appears from inside boiler from joint subsequently named as the multi hydraulic connector click here for photo. Leak fixed. Short lived success, spend next hour tightening all visible joints under boiler.

7. Speak to Ariston, they suggest that it is more than likely to be a leak in the system. I part drain system add leak sealant. Short lived success as pressure now falls to zero faster than ever (from 1.5 - 0 in about an hour)

8. Pull up most floor boards to check joints etc...nothing leaps out at me as prolonged and substantial leak.

I am now in a position of not knowing what to do next.

During this whole time the boiler appears to be working well.

When the resting pressure is 1.5bar the operating pressure is just under 2bar (it has gone over a couple of times, usually immediately after one of the remedies mentioned above).

The water heats to approx 90 degrees (should it be hotter?)

What do I do now? Has this gone beyond DIY? Should I call in an "expert"? Can anyone recommend someone in Leyton E10?

Thanks in advance for any advice and thanks if you got this far in reading my post.


Curtis

 

[oilman]

This illustrates the benefit of employing the right person for the job. I suggest you get someone who makes a living out of fixing things like this. You've only got the bricks and tiles to replace and it's a complete new house.

 

[curtis]

Cheers for that.

Well, I've only been a homeowner for a couple of months and I've already got dry rot and a heating system thats knackered.... so I think I can be forgiven for at least trying the basics before getting someone in.

Can anyone recmommend anyone in East London?

thanks

Curtis

 

[ChrisR]

I've done a fair bit of fiddling with sealed systems, & I think I'd have gone along the same route as curtis. THe usual places to look for leaks is at radiator valves. check round the stems for signs of corrosion products. Many rad valves are 85p crap with no stem seal nut.

Some people don't realise that raising the pressure in the pressure vessel makes leaks look dramatic where they were hardly noticed on the gauge before. (Think about it!)

If you really can't find the leak the approach is crude - put isolating valves (of the right type) in the system and run it again to see if you've isolated the leaking bit.

 

[universe]

Curtis, just thinking loud:
Is it 200% certain that water is being lost? - ie faulty gauge.
Can you close ALL pipes/radiators, leaving only one open to help the pump and then see if the problem still exists.
If everything is closed and still loosing water for sure (and the short pipe circuit is OK) then it's got to be inside boiler (leaking heat exchanger).
If everything closed as explained above, and no loeak, then isolate one radiator at a time to find which pipe route.
Isn't there a safe dye that can be used? - NOT washing up liquid.

 

[curtis]

The boiler is losing pressure so quickly that it has to be water. It's now not heating the water that well either.

But on the positive side I think I've found the leak. Early this morning I filled it up and heard a faint hissing noise under the floorboards, under the kitchen units....so I think I've found my problem.

Thanks for all your advice....I've decided to join the British Gas Maintainence contract unless anyone here can tell me why I shouldn't.

C

 

[ollski]

Thanks for all your advice....I've decided to join the British Gas Maintainence contract unless anyone here can tell me why I shouldn't.

C

I would repair the leak and not mention it then when you get your first visit.

 

[curtis]

but...it's in one of the most inaccessible places in the house (fitted kitchen units etc) and I am a beginner to all this DIY nonsense. So I thought that the annual cost of the agreement is easily lower than getting someone else in to chop up the floorboards (nicely stained and varnished) and fix the pipe.

C

 

[Damien]

Curtis - nice to know i'm not the only one having boiler problems in my new flat this year!!! Every day I set the timer and everyday the pressure has returned to zero and no heat/hot water! The land-lord has mentioned a leak somewhere but now I have read your story I am going to print it and shove it in his face for him to pay for!

 

[yelloweagle]

Hi Guys,

Posting this one in several places,
just in case someone else has the same problem....



I've an Ariston SX20, but am sure that most combi-boilers
will produce the same symptoms, and be cured
in the same relatively simple manner.

I was losing pressure ... until tonight it was
a top-up with the filling loop every morning and night.

I initially went along with the idea of a leak,
but finally several symptoms pushed me
in the direction of investigating the
expansion tank in the boiler itself.

The symptoms:

************
From a top up every few months,
the intervening period came shorter and shorter.

A top-up used to take up to ten seconds,
it now pressured up almost immediately.

On firing up the central heating the pressure
would increase drastically from the advised 1.0 bar;
until it finally opened the safety pressure release valve.
************

Had a word on the phone with my friendly local
plumbing spares supplier and he told me what
would be required to re-prime the expansion tank.
On the way home tonight I popped into Halfords
and bought a high volume bicycle pump suitably for a BMX. £6.50.
(There are two main sizes of bicycle valve,
the Ariston uses the larger, and I was advised
that most boilers are standardised in this)

Imagine the expansion tank with a diaphragm
laid across its central axis. One half should be filled with air.
In my case, the air had vanished during the six years of its operation,
much in the same way that a car tyre loses air pressure over time.

In this scenario, as soon as the boiler fires up,
because the expansion tank is already virtually full of water,
the water in the sealed system has nowhere to expand to.

As previously stated,
on firing up the boiler, the pressure
would increase drastically from the advised 1.0 bar;
until it finally opened the safety pressure release valve.

In the case of the Ariston SX20, the priming valve
is situated at the back of the boiler.
There is no need to take the cover off the boiler,
it will be seen on the right hand side of the tank,
when looking from above;
hopefully with the original dust cap still on it.

The expansion tank in this model has a capacity of seven litres.
Ariston manual is available as download from...

http://www.centralheating.co.uk/ind....memberDetail/con_id/6444/directoryGroup/5344

...but it doesn't help with this problem.


Here's how I managed the tricky bit:

1. Find the nearest system drain valve, attach a short hose
and place a container at least 4 litres capacity under it.
2. Remove dust cap and attach the bicycle pump to the tank valve.
3. Start pumping the pressure up, until it reaches 1.5 - 2.0 bar.
4. Drain the system a little until the pressure approaches zero.
5. Repeat 4 and 5 until there are approx 3.5 litres
in the container under the system drain valve
(or however much you decide upon for your make of boiler).
6. Leave the pressure primed up to 1.0 bar.
7. Quickly remove the pump so that
not too much air is lost through the valve.
8. Replace the dust cap.

Here I was, thinking this was going to be as expensive as it gets.

P.S. This is all your baby,
I'm offering no guarantees;
suffice it to say that it worked for me.

Happy householding.
John.

 

[croydoncorgi]

Oh dear - why make things so complicated?

The valve on an EV is a standard Shrader valve - as found on ALL car tyres (and some bikes). It IS a valve, so if air comes out of it when you remove the pump, it's broken!

To restore the EV preload the procedure is utterly simple:

- decide what the preload should be, based on the system working pressure. (For a standard system, it's usually 1 to 1.5 Bar. 0.75 X the working pressure is the usual preload.)
- get all pressure off the EV. (If it's inside the boiler, isolate the boiler and drain it until the gauge pressure is zero. If it's elsewhere, drain water off until the gauge on the EV reads zero.
- check the pressure in the EV and pump up or release air as necessary.
- refill to correct pressure.

When the system heats up,the pressure will rise slightly but with the preload set as indicated, this rise will be minimised.

 

[gas4you]

Thanks for all your advice....I've decided to join the British Gas Maintainence contract unless anyone here can tell me why I shouldn't.

How long have you got

 

[bengasman]

Thanks for all your advice....I've decided to join the British Gas Maintainence contract unless anyone here can tell me why I shouldn't.

C

The reason? You mean the reasonS. Apart from many people finding it very poor value for money, it is unlikely they will take on a boiler that has problems already. Yes, being an independent rgi, I am probably biased. Yes, it is hearsay as I obviously do not need them. fact is, I have a number of clients who used to have bg and were displeased with the service to put it mildly.
One simple bit of advice, do a search for bg on this forum and see what you think about your findings