Low water pressure in Bolier only after turning on heating

manan.shah.82

Just to help out anyone like me,

PRV = Pressure Release Valve

southcoastrgi

Canucklehead wrote: »

Hi.

When the boiler was serviced was the EV checked?
If not then it should have

no i totally disagree, it says no where in the servicing instructions about checking the EV pressure & like i said the boiler will need to be empty & under no pressure to test this, the EV is situated at the back of the boiler, if you have a side flue you need 340mm above the boiler to change it, if you have a vertical flue you need the same access size to the side, if you don't have these distances the boiler will need to be removed from the wall or an external 7 ltr EV can be fitted, good old WB lets not make it hard to work on, most expensive boiler to buy & most expensive to service & repair due to carp design.

macman

manan.shah.82 wrote: »

Thanks for the information but what is prv? and to be honest I don't know where EV is located? how can I find it out?

I had a look at the manual but couldn't find anything helpful..

considering I have no idea about it should I call some corgi certified engineer for this or is it something really simple which anyone can do? I don't want to spend much money on simple thing but at the same time I don't want to make things worse...

The PRV is attached to an overflow pipe that goes out through the wall-not too hard to locate. CORGI is obsolete, you need a GSR (Gas Safe Register) RGI if you can't do this yourself.

Canucklehead

southcoastrgi wrote: »

no i totally disagree, it says no where in the servicing instructions about checking the EV pressure.

So that leads to the question , when do you check the EV?

Maybe that's the difference between an RGI taking the time to check more than just flue gas, than the ones who take pride in doing a 'service' in 10 minutes so they can brag about how little time it took to their mates down the pub.

I'm not sure which combi you have in mind where the EV precharge is 3.5 bar or are you thinking the EV on an unvented DHW cylinder?


GSR.

southcoastrgi

Canucklehead wrote: »

So that leads to the question , when do you check the EV?

Maybe that's the difference between an RGI taking the time to check more than just flue gas, than the ones who take pride in doing a 'service' in 10 minutes so they can brag about how little time it took to their mates down the pub.

I'm not sure which combi you have in mind where the EV precharge is 3.5 bar or are you thinking the EV on an unvented DHW cylinder?


GSR.

a good question, & yes you can't service a boiler in 10 mins for starters i always do a co leak test on top of the boiler & this takes 15 mins on my anton, however i have never seen anyone release the pressure within a boiler to test the EV unless the MI asks for it, & that is the difference between a reg RGI & one that does servicing if you know what you are doing & ask the customer if they have had any pressure probs with regard to the gauge then you can normally tell if there is a problem with the EV as you know, yes i agree with regard to the pre charge however i did say some are 3.5 bar sorry i should have made myself clearer i was just trying to make the point with regard to re pressurising.

Canucklehead

Hi.

So this is where the OP came in with his problem.

Boiler has been 'serviced'.
At that time (6 months ago) there was no problem as the OP had no need to run the c/h so would not see the results of a low EV precharge.
Now the heat is on it's a problem.

Had the EV been checked at the time of service there would probably not be a thread entitled 'Low water pressure in Bolier only after turning on heating'

Not all customers are aware of what's going on in their boiler or system, that's why they call like likes of us to make sure it's up to scratch.


GSR

gas4you

Most EV's need to be around 0.75-1bar.

I always ask the customer/tenant if they have had to top up the pressure regularly and if they say yes, then I drain and check the EV pressure.

If they say no, then I don't bother, unless it is a Vaillant Ecotec Plus, which will always need the EV re-pressurising at a service.

manan.shah.82

Guys thanks a ton for all the replies..

I think today I have located a Expansion Vessel valve, as describer in earlier thread, it's located at the top rear side and when I removed the cap it looks similar to the valve usually we can see in bicycle or car.

Few questions,

1. I have a Single Barrel bicycle foot pump. Can I use that to check the pressure and feel the pressure. Though not sure I will be able to use that because my boiler is located above the kitchen worktop...

2. What should be the correct pressure? Model is Worcester Greenstar 24i, I couldn't find any mention about the EV pressure in the manual I have.

3. What if I accidently over pressure it? Can I use the some like needel to release the extra pressure?

4. Some one mention that before checking the EV pressure or re-pressurising, boiler should not have any pressure? does this mean water pressure? Can I just bleed my radiator until the water pressure gauge is 0?

Thank you very much once again for all your support.

Regards

southcoastrgi

0.75 bar or 11 psi if the ev has water in it when it is re-pressurised the water needs to go somewhere, therefore you can't let the pressure build back up in the boiler/heating system or you will get a false reading, if you drain the heating system then you will need to re-fill it with inhibitor

manan.shah.82

Guys,

Thank you very much for all your support and replies.

I have repressuries the EV using the foot pump but when I took out foot pump lead some air escaped (which is fine and I expected) but it smelled like gas for few seconds as well. Is that normal? Is it safe to turn on the boiler?

Can someone please reply asap?