Refilling central heating with no electricity available - is this normal?

phatony

Hi,

I am refilling the central heating system in my first ever house which has no electricity at the moment. Filling happens by simply turning on mains supply.
Bleeding lower and then upper rads in turn. House has zone valves in hotpress.


Couple of weird things. Drain off at bottom of system only emptied half downstairs rads.
Had to drain off elsewhere for other half.
When refilling, one rad in utility room with boiler didn't seem to get water, but rest of downstairs rads filled.

Filling of system very slow. The dial on the potterton boiler never moved above zero bar.
Also, filling of rads upstairs agonizingly slow, leaving it until tomorrow evening to go back and bleed off again upstairs.

No electricity probably means zone valves could be closed or open.
I think the pump is inside the boiler.

Questions: Is it normal for the boiler not to register pressure unless started?
Any comments on the rest of the above?

Thanks

Sleeper12

It sounds to me that the heating is not fed by the mains but by an attic tank. This could be very slow in a big house. The pressure gauge will stay at 0 bar till the system is full or until you stop venting & allow the pressure to build up. If you are filling from a tank you can expect half a bar of pressure. If you are filling from mains expect more.
If it is actually mains could the pressure be so bad that it has a pump? Pump won't work without electricity. Is the valve fully open?

phatony

Sleeper12 wrote: »

It sounds to me that the heating is not fed by the mains but by an attic tank. This could be very slow in a big house. The pressure gauge will stay at 0 bar till the system is full or until you stop venting & allow the pressure to build up. If you are filling from a tank you can expect half a bar of pressure. If you are filling from mains expect more.
If it is actually mains could the pressure be so bad that it has a pump? Pump won't work without electricity. Is the valve fully open?

I think there is a vented tank yes, but the attic is a small hip-roof with no floor, can't easily get into it.

It is just a small 3-bed semi.

I opened the valve (the main valve under the sink) enough to get good gush of water at tap and it filled the loft tanks for sure - this also fills the heating - but technically it may not be fully open.

I left mains on overnight so I will see what happens with the pressure guague when I go back tomorrow.

Do you have to bleed at pump - which i guess is inside boiler?

scudo2

Zone valves have a lever that should be put in the open/manual position temporaly if your filling or draining the heating.

It will fill / drain easier that way.

Sleeper12

phatony wrote: »

I think there is a vented tank yes, but the attic is a small hip-roof with no floor, can't easily get into it.

It is just a small 3-bed semi.

I opened the valve (the main valve under the sink) enough to get good gush of water at tap and it filled the loft tanks for sure - this also fills the heating - but technically it may not be fully open.

I left mains on overnight so I will see what happens with the pressure guague when I go back tomorrow.

Do you have to bleed at pump - which i guess is inside boiler?

Ok its my guess that you have a small tank in the attic for the heating system. This tank only holds a few litres. This tank is fed by the mains. Because it only holds a few litres it's very slow filling the heating system.
There must be another valve just for the heating system. This could be in the hot press or at the boiler. Maybe this isn't open fully.
You'll get there. It'll just take time.

phatony

Scudo2 was right about levers but I discovered that two of the 3 actuator clips were broken and they were just sitting in place.

So I took actuators off, turned the valves counterclockwise and was able to fill all but two of the radiators - slow but not as slow as before.

Anyway, of the radiators I cannot fill...
One radiator is downstairs next to the boiler, the other in the upstairs bathroom.

I discovered that the lockshield on the one in the utility was closed all along, bathroom was open ok.

So the fact that I filled the system will all radiators open except for the downstairs utility - could that cause an "airlock" or something like that which prevents me from refilling?

Should I have closed the upstairs rads, filled downstairs, and then filled upstairs?
Is the fact that I can't fill the upstairs rad not unexpected, because I messed up the order?

If I have to drain down and start again, should I fill with just the upstairs rad valves in the off position, or should I close the upstairs lockshields as well?
Several online resources recommend different things, I don't know which to follow!

Also, do I need to bleed the pump, which is probably inside boiler?

Gawd I'm such a plumbing newb!

Sleeper12

phatony wrote: »

Scudo2 was right about levers but I discovered that two of the 3 actuator clips were broken and they were just sitting in place.

So I took actuators off, turned the valves counterclockwise and was able to fill all but two of the radiators - slow but not as slow as before.

Anyway, of the radiators I cannot fill...
One radiator is downstairs next to the boiler, the other in the upstairs bathroom.

I discovered that the lockshield on the one in the utility was closed all along, bathroom was open ok.

So the fact that I filled the system will all radiators open except for the downstairs utility - could that cause an "airlock" or something like that which prevents me from refilling?

Should I have closed the upstairs rads, filled downstairs, and then filled upstairs?
Is the fact that I can't fill the upstairs rad not unexpected, because I messed up the order?

If I have to drain down and start again, should I fill with just the upstairs rad valves in the off position, or should I close the upstairs lockshields as well?
Several online resources recommend different things, I don't know which to follow!

Gawd I'm such a plumbing newb!

All rads upstairs should be closed. Fill downstairs first then work your way upstairs. One rad at a time.

phatony

Sleeper12 wrote: »

All rads upstairs should be closed. Fill downstairs first then work your way upstairs. One rad at a time.

Can I leave the lockshields open upstairs and just close the on/off valve?
Also, when you say one rad at a time, what do you mean exactly?
Open and bleed one at a time? Does the order matter when upstairs?
Thanks

Sleeper12

phatony wrote: »

Can I leave the lockshields open upstairs and just close the on/off valve?
Also, when you say one rad at a time, what do you mean exactly?
Open and bleed one at a time? Does the order matter when upstairs?
Thanks

Shutting the rad at 1 end is fine. The on off valve is fine.

If you had lots of pressure you could fill several rads at the same time but as the pressure is so bad I would do one at a time. Open one valve, fill the rad. Then move on to the next one.

phatony

Sleeper12 wrote: »

Shutting the rad at 1 end is fine. The on off valve is fine.

If you had lots of pressure you could fill several rads at the same time but as the pressure is so bad I would do one at a time. Open one valve, fill the rad. Then move on to the next one.

Ah that pressure thing is an excellent point, thanks.

phatony

It turned out that all my problems related to two radiator bleed vents vents being blocked - even stopped the boiler from filling!

Sleeper12

phatony wrote: »

It turned out that all my problems related to two radiator bleed vents vents being blocked - even stopped the boiler from filling!

Glad you got it sorted. ☺

phatony

although boiler pressure gauge not quite touching 0.5 bar...

Sleeper12

As you seem to fill your system from a small tank in the attic & not the mains this is normal. You gain .25 bar of pressure every 10 foot. So tank in attic to ground floor is .5 bar