Bled radiator while heating was on and now boiler pressure is too low to ignite

Participant · 14 Mar 2013 at 18:37

Hello ocuk

I made the rookie mistake of bleeding a radiator while the heating was on. So I come downstairs feeling pretty chuffed with the amount of air I'd let out, before realising that the heating wasn't working. Tried resetting the boiler and it fires for a second before conking out. Pressure gauge is reading 0.25 bar.

I've read about letting more water into the system, but when I open the stopcock valve on the cold water inlet to the boiler, it just spews water out of a nut on the side.

Any help is gratefully received.

Fourstar · 14 Mar 2013 at 20:04

Do you have something like the image below?

The top fitting is the isolator that needs opening. The bottom fitting with the nut in is a double check valve so water can flow into the heating system but not back out. The arrow on it shows the direction water flows through it.

Did you loosen the nut? You can tighten it back up if loose. I don't actually know if the nut has any use other than for testing the valve is working correctly.

Glaucus · 14 Mar 2013 at 20:08

You just need to refill it. This depends on the boiler. So google the manual for your make and model. Some are more complicated than just a simple tap.

Participant · 14 Mar 2013 at 20:17

fourstar - hmmm sort of, except those two valves seem to be on different pipes:

The black valve I've tried opening and closing, likewise the little blue one above it. I've read about filling loops, except mine doesn't seem to have one?!

Glaucus, I have the physical manual in front of me. It just says open the fill valve.

mattyg · 14 Mar 2013 at 20:22

Whenever you bleed the boiler your letting out pressure. Whether on/off wouldnt make any odds. You'd still need to replace all that air with water.

In the back of the manual does it not show which connection is to fill

Participant · 14 Mar 2013 at 20:34

Nope

. Have now connected the two pipes with a shower hose. Wish me luck.

Fourstar · 14 Mar 2013 at 20:36

So the water is coming out around the big brass coloured nut on the valve with the black handle?

Can't see in your pic if the black handled valve looks like the one in the pic below ie the valve operates on the opening from the "T" pointing towards you not on the vertical pipes.

It looks to me like there should be a flexible pipe connecting that valve where the nut is attached to the check valve on the right of your photo. Are you renting? If so I guess the landlord removed it on purpose.

I may be wrong as I can't be sure what the different pipes actually are in the photo.

Haze · 14 Mar 2013 at 20:39

Robbie G said:
Nope . Have now connected the two pipes with a shower hose. Wish me luck.

you are joking right :confused:

the government banned home owners like you from doing there own diy for a reason

Nightglow · 14 Mar 2013 at 20:40

You need to get water from rising main into boiler ch side, you need a filling loop.

Connect filling loop from brass nut black handle pipe to chrome valve on the right.

What boiler is it?

mattyg: You bleed the radiators with the boiler off, less chance of pump bringing more air in to system.

You always need to keep a eye on the pressure when bleeding & don't let it drop too far, & keep topping up the water.

mattyg · 14 Mar 2013 at 20:53

Nightglow said:
You need to get water from rising main into boiler ch side, you need a feeling loop.

Connect filling loop from brass nut black handle pipe to chrome valve on the right.

What boiler is it?

mattyg: You bleed the radiators with the boiler off.

My point was he'd still need to refill whether he did it when the boiler was on/off Maybe the full stop changed the reading of the sentence. (which you'd expect from a full stop

)

Participant · 14 Mar 2013 at 21:02

Haze said:
you are joking right

the government banned home owners like you from doing there own diy for a reason

Well as with everything, you have to pick and choose which advice you heed on the Internet. And thankfully for me, I ignored yours.

With a bit of ptfe tape on the threads, the shower hose worked perfectly. I connected the two pipes with valves on with the hose then slowly turned the black valve. Pressure started rising slowly and our radiators are now red hot once again! So thank you so much everyone that isn't haze; I actually love this new forum section.

Ps it's a ravenheat csi120 boiler. Came with the house we bought in December. Too small for the property by all accounts, but it's done a great job so far. Just for some reason there was a tonne of air in the towel heater in the main bathroom.

Anyway, all sorted now and thank you again!

Fourstar · 14 Mar 2013 at 21:05

Haze said:
you are joking right

the government banned home owners like you from doing there own diy for a reason

To be fair to OP a simple DIY task has been sabotaged by [someone] and he's now shivering at home on a freezing night.

I was quite impressed with his lateral thinking using a shower hose though I must admit I'm not sure how sure he was before trying!

dholdi · 14 Mar 2013 at 21:12

The filling loop should be disconnected when not in use according to the water bylaws, however total removal and hiding it is unnecessary.

Good thinking with the shower hose.

I would put a stop end on the check valve, as if the washer goes on it, it will pour out, and that usually happens when you are not at home.

Nightglow · 14 Mar 2013 at 21:16

Robbie G said:
It's a ravenheat csi120 boiler. Came with the house we bought in December. Too small for the property by all accounts, but it's done a great job so far.

Save up & treat yourself to a Valiant boiler.

dholdi · 14 Mar 2013 at 21:24

Is that a very brave boiler

Fourstar · 14 Mar 2013 at 21:25

dholdi said:
The filling loop should be disconnected when not in use according to the water bylaws,

Does that ever actually happen in practice?

I've never seen one disconnected (with the exception of this thread) and the 4 different plumbers I use for annual gas safety certs have never disconnected the filling loops.

dholdi · 14 Mar 2013 at 21:32

Fourstar said:
Does that ever actually happen in practice?

I've never seen one disconnected (with the exception of this thread) and the 4 different plumbers I use for annual gas safety certs have never disconnected the filling loops.

Your right, it rarely happens, but technically it should be.

spoffle · 14 Mar 2013 at 21:34

Haze said:
you are joking right

the government banned home owners like you from doing there own diy for a reason

I bet he knows the difference between "their" and "there" though!

To be fair to the OP, everyone has to start somewhere, people aren't born with knowledge of everything they are interested in.

Participant · 14 Mar 2013 at 21:56

dholdi said:
The filling loop should be disconnected when not in use according to the water bylaws, however total removal and hiding it is unnecessary.

Good thinking with the shower hose.

I would put a stop end on the check valve, as if the washer goes on it, it will pour out, and that usually happens when you are not at home.

I will do that. And I will also get a proper filling loop pipe. Though I suppose if I leave the filling loop connected I will a) never have to worry about the valve breaking and b) be able to instantly repressurise the system if required.

System is now reading 2 bar with heating on full pelt. Towel heater in second bathroom is a slightly less boiling at the top so I guess I'd better bleed that too!