Protherm 80E expansion vessel, where is the valve???

[greg123]

Hi guys,

Thanks to you we have 2 previous problems fixed on the Protherm 80E boiler!

Thanks to Protherm it has broken again....

After searching (see, I'm learning! ) I have identified a leading PRV, which I have sourced, but I suspect from the non stable high>low pressure behaviour and having to regurlarly top up, that the expansion vessel has a split diaghpharm. The pump also failed, but I traced that to rotten multip plug connector going into the pump, rewired it and now the pump is fine. Not sure why those terminals corroded when the earth one didn't (3 terminal multi plug) and all other electrics are clean, no leaks from the pump or water in the electric connection box on top of it but hey.

Problem is, in the 80E manual very little reference is made to the expansion vessel. From the diagram and the flexible 15mm pipe, it looks like it's behind the boiler/burner, against the wall. I can't see a schrader valve anywhere to check it's pressure and try topping the air up if it's low or test for water. Surely you don't have to remove the combi just to check the pressure?????

Can anyone help me identify/check the expansion vessel on 80E? I can get a new one for £45+vat if faulty but at least want to check this first.

Also searching and manual didn't shed much light on what the tyre valve cap type thing on the pump block is, and why is it going green (should water come out) I read about an aav but I don't know what that is, can anyone explain? Protherm manuals are pants.

Greg.

 

[petit_pablo]

Get up above the boiler and look down the back, you should find the top of the expansion vessel and a shraeder valve

 

[Gasguru]

You're not looking hard enough. It will be on the vessel somewhere but due to incompetent design sometimes the schraider valve is not accesible (ie it points to the wall etc). Have you looked down the back of the boiler....some boilers require small cover plate/bracket to be removed.

I suspect the "tyre cap" on the pump block is just the auto air vent...the cap should be loosened a turn or two. However they often leak but are a cheap part to replace. Examples below are off the carp Glowworm/Saunier Duval models

Glowworm Compact/ Suanier Duval SD30

• Gasguru
• 2 May 2008
• 2

The design team provide more evidence of theie ineptitude. Schraider valve faces the wall.

Glowworm Compact/ Suanier Duval SD30

• Gasguru
• 2 May 2008
• 5

If the vessel can't be levered away from the wall you will need to bolster a lump from the...

 

[greg123]

Pablo, thankyou.

Got it. 18psi, valve looks dry, no water came out. When I get a bicycle pump out so I can re-pressurise I'll try letting all the air out and putting system pressure back to make sure that no water comes out. Then I'll let system pressure out and set the expansion vessel pressure as per the book (1.5 bar I think) with no pressure in the CH - from reading the maunual that seems to be the correct way to do things, then top up the CH water pressure to 1-1.5 bar.

Any idea what the other 'valve cap' on the pump casting/body is for? And if water should come out of it?

Greg.

Get up above the boiler and look down the back, you should find the top of the expansion vessel and a shraeder valve

 

[greg123]

Thanks Gas,

I wasn't - you were right, get my head in the ceiling and it's down the back of the boiler and quite accessible, presuming you are not tight to the ceiling with the combi!

As for the AAV as I now understand it from what you say, it's green all around it and if I take the cap of water runs out, not drips, runs. Any thoughts on that or do I just order a new AAV? Greg.

You're not looking hard enough. It will be on the vessel somewhere but due to incompetent design sometimes the schraider valve is not accesible (ie it points to the wall etc). Have you looked down the back of the boiler....some boilers require small cover plate/bracket to be removed.

I suspect the "tyre cap" on the pump block is just the auto air vent...the cap should be loosened a turn or two. However they often leak but are a cheap part to replace. Examples below are off the carp Glowworm/Saunier Duval models

Glowworm Compact/ Suanier Duval SD30

• Gasguru
• 2 May 2008
• 2

The design team provide more evidence of theie ineptitude. Schraider valve faces the wall.

Glowworm Compact/ Suanier Duval SD30

• Gasguru
• 2 May 2008
• 5

If the vessel can't be levered away from the wall you will need to bolster a lump from the...

 

[Gasguru]

NO, no, no, no the expansion vessel should only be set to around 0.8 bar (about 12 psi). Only check the pressure with the system pressure at ZERO and pump up if necessary. Afterwards set the water pressure to 1 Bar (certainly no more than 1.5 bar) with the radiators COLD and the boiler pump not running.

These figures are auusuming you are in a standard 1 or 2 storey property.

Replace the auto air vent.

 

[WDIK]

18psi is near enough to 1.2bar leave it alone what you can do and others will advise as im a commercial engineer, find out how the vessel is connected to the system, i know some use a flex pipe which can apparently clog?

 

[petit_pablo]

18psi is near enough to 1.2bar leave it alone what you can do and others will advise as im a commercial engineer, find out how the vessel is connected to the system, i know some use a flex pipe which can apparently clog?

These are a flexi pipe onto system.

 

[WDIK]

Im sorry I didnt know that

 

[greg123]

Good point Gas I forgot to make sure CH pressure was zero. I'll check it again after dinner. I looked up the pressure and it's supposed to be 1 bar according to the service manual.

I'll post back when I have done the above/below.

Greg.

NO, no, no, no the expansion vessel should only be set to around 0.8 bar (about 12 psi). Only check the pressure with the system pressure at ZERO and pump up if necessary. Afterwards set the water pressure to 1 Bar (certainly no more than 1.5 bar) with the radiators COLD and the boiler pump not running.

These figures are auusuming you are in a standard 1 or 2 storey property.

Replace the auto air vent.

 

[WDIK]

but I suspect from the non stable high>low pressure behaviour

listen!!!!!

the symptom are the same as having a flat vessel

same as vessel not connected due to a blockage

 

[greg123]

It has a flexi hose, should i take it off or just read pressure after I drop CH pressure to zero and if the expansion vessel pressure goes down some presume that the flex hose is okay?

Greg.

18psi is near enough to 1.2bar leave it alone what you can do and others will advise as im a commercial engineer, find out how the vessel is connected to the system, i know some use a flex pipe which can apparently clog?

These are a flexi pipe onto system.

 

[greg123]

That's fair and makes sense, how would you advise I test for this, remove and manually check the flex hose or other method?

but I suspect from the non stable high>low pressure behaviour

listen!!!!!

the symptom are the same as having a flat vessel

same as vessel not connected due to a blockage

 

[WDIK]

open a bleed on a rad, drop to zero and then check the flex

 

[petit_pablo]

If i suspected blocked exp vess hose i would drain boiler, remove flexi hose and repressure exp vessel with hose disconnected. If its blocked, nothing will come out of hose. If it snt, beware, alot of muck and water will shoot out! You may need an extra pair of hands for this bit!!