Is my boiler okay with no expansion vessel?

[Dan]

Hi,

My boiler has had no expansion valve for 18 months now. A plumber said it needed a remote one on it but never came back. I can't preheat my water and it's getting annoying now (see how laid back I am? it takes 18 months to annoy me).

Is it okay to just whack the preheat up or what?

 

[diamondgas]

Re: Is my boiler okay with no expansion valve?

Do you mean expansion vessel Dan? If so the fact that it's lost it's charge should have no bearing on the preheat. IMO

 

[Dan]

Re: Is my boiler okay with no expansion valve?

Sorry yes I think I mean expansion vessel as he said 'lost it's charge we tried to yada yada it and couldn't'. Sorry did I get you worried there haha my bad.

So you think I should be okay preheating?

What's this vessel do then? I assumed it was regulating pressure but I guess my expansion 'valve' does that then does it?

 

[diamondgas]

Water expands when heated and the expasion vessel is a charged bellows that takes up that expansion. Without it the pressure in the system would get to high! Do you find the gauge pressure rises quite a bit, say from 0.5 to around 3? Do you know the make of boiler Dan?

 

[Dan]

Baxi 105

It idle's at zero when radiators are not on. Goes up to about 1.5bar when they're on. Never tried preheating as I literally thought I'd blow the house up. But it's getting annoying now as we have a little girl (6 months old) and we're using a lot more hot water for various things including more showers/baths due to being covered in sick so often. ha

 

[diamondgas]

Put the preheat on and keep an eye on the pressure, you can't blow yourself up as there's a safety valve fitted that'll prevent the boiler going over 3 bar! You really need to get the EXP vessel sorted though! Sometime you can get away with just re-charging the vessel though Dan. If your original plumber didn't try this out then best get someone in for a second opinion ... IMO

 

[Billy Bob Bob]

its a 105 instant for my sins i know this boiler backwards is it a standard efficiency or high efficiency Dan

 

[Mike Jackson]

Hi,

My boiler has had no expansion valve for 18 months now. A plumber said it needed a remote one on it but never came back. I can't preheat my water and it's getting annoying now (see how laid back I am? it takes 18 months to annoy me).

Is it okay to just whack the preheat up or what?

I'm sure some one from on here would nip round and have a look for you in thanks for your work on the forum.

 

[armourer]

I also would not expect too much of a change with pre heat on, dependent on the length of pipe runs to the taps.
Imo it works fine on a short run if you just turn the taps on then straight off again but if you run any more than that, you get the water hot , then cold, then steadily to hot again and stay there.

 

[jhon lennon]

you are putting pipes under a lot of pressure and need to sort your expansion tank out be four the pressure relief valve operates because they rarely re seal and swapping one is a bit of a pain

 

[Roger Welton]

Plus the constant cycling of pressure from high to low can cause fatigue failure of joints and materials, does need sorting one way or another.

 

[Dan]

Put the preheat on and keep an eye on the pressure, you can't blow yourself up as there's a safety valve fitted that'll prevent the boiler going over 3 bar! You really need to get the EXP vessel sorted though! Sometime you can get away with just re-charging the vessel though Dan. If your original plumber didn't try this out then best get someone in for a second opinion ... IMO

He did try to re-charge it, I remember him saying that. He said I'll need a remote/external one on it but then never came back sort of thing.

its a 105 instant for my sins i know this boiler backwards is it a standard efficiency or high efficiency Dan

I'm not too sure how to tell mate, just had a quick look around it. The only marking says 'Baxi Instant 105e' - don't know if that helps at all.

I'll give the plumber a call again and give him a nudge then. Though I will try (when I'm in long enough to monitor it) preheating and seeing what bar the pressure reaches. If it manages to stay below 3bar I'm guessing I'd be okay to run with it like that?

 

[Billy Bob Bob]

on your boiler Dan its a instant version so its under far more strain than a normal combi its expansion vessel is also its thermal store,having a faulty EV on this boiler is bad news it will put the heat exchanger o rings under a lot of strain on the he version when the o rings go they can run down the wiring loom taking out the pcb on the standard efficiency version this is less of a problem as the heat exchanger connections are in a different place if you fit a external ev you can no longer use the pre heat facility if you go back with a OE EV you can use preheat not a good idea to use preheat with a dodgy ev if its been 18 months its more than likely not able to be pumped up,if your plumber has concerns about changing the original part it can be done in situ but can be very difficult baxi say the boiler has to come off the wall this is not to hard a job though to be honest

 

[Dan]

Plumber has been back and has stuck a huge red bubble/tank (I'm guessing it's the expansion vessel) under the boiler and has replaced 3 stat valves that had packed in too.

Thanks for your help lads.

 

[Barry98]

Plumber has been back and has stuck a huge red bubble/tank (I'm guessing it's the expansion vessel) under the boiler and has replaced 3 stat valves that had packed in too.

Thanks for your help lads.

How much that rush you mate, wish I'd seen post earlier I have a spare new one you cold of had cheap