Anyone know anything about central heating?

RedRabbit

I've got a kerosene boiler and with the bad weather I couldn't get any oil delivered so have been without heating for the last few days.  I've also had a pipe burst so until a plumber comes on Thursday I'm also without water.

The oil finally got delivered today and, after bleeding the system, I've managed to get the boiler to fire.  Left it running for a few minutes and went back to check it and all seemed fine.  Closed it all up and settled down.

A little while later I noticed that the radiators weren't getting hot and, on checking the boiler it had shut itself but wasn't showing the usual warning light so I think it's still getting oil.

I was assuming that the water used to heat the radiators would be a closed system so didn't think the water being off would be an issue (I'm sure I've had the heating on while the water's been off before) but I'm now wondering if the lack of water is the problem.

Any one any idea?  Don't really want to call in the heating engineer if it's just a case of waiting 'til the water is back on.

darthed1981

Not an expert at all but my boiler has a loop to allow you to repressurise it though it does helpfully tell you when you need to do it!, it's a gas combi job though so not the same thing but maybe you could check your manual?

Nikc

Make sure it has enough water pressure is it a combo boiler ?? 
Usually oil boilers have an optical check that needs to be clean if not no fire up 

RedRabbit

Cheers but I think I've managed to find the answer.

When the water leak started I turned the water off and turned the taps on until the ran dry.  In doing so I've emptied the cold water tank which is what the boiler feeds off to pump water around the radiators.  In the past when the water has gone off there's always been water in the tank which is why I've been able to keep the heating on.

Looks like I'm waiting until the plumber gets the water back on and see where we are then.

At least it's warmed up outside.

boogieman

RedRabbit said:

Cheers but I think I've managed to find the answer.

When the water leak started I turned the water off and turned the taps on until the ran dry.  In doing so I've emptied the cold water tank which is what the boiler feeds off to pump water around the radiators.  In the past when the water has gone off there's always been water in the tank which is why I've been able to keep the heating on.

Looks like I'm waiting until the plumber gets the water back on and see where we are then.

At least it's warmed up outside.

That sounds a very odd system indeed. The radiators in an open system shouldn’t be connected to the cold water tank (which you say you emptied when you turned on the taps) because there’s chemicals and hot water in the radiator system that shouldn’t get anywhere near your cold water tank. There should be a completely separate smaller feed and expansion tank that tops up your radiators. 

Nikc

oh dear not good 

RedRabbit

I know next to nothing about central heating so I'm just going off some info I found online.  The first time I had to bleed the system to get the oil running it took me hours of research for what turned out to be a 5 minute job.

Got the info from this site - https://www.nihe.gov.uk/index/advice/maintaining_your_home/winter_maintenance/water_supply.htm

RedRabbit

Nikc said:

oh dear not good 

Care to elaborate?

boogieman

RedRabbit said:

I know next to nothing about central heating so I'm just going off some info I found online.  The first time I had to bleed the system to get the oil running it took me hours of research for what turned out to be a 5 minute job.

Got the info from this site - https://www.nihe.gov.uk/index/advice/maintaining_your_home/winter_maintenance/water_supply.htm

In which case I would leave it to a plumber/heating engineer to sort out if I were you. 

RedRabbit

boogieman said:

RedRabbit said:

I know next to nothing about central heating so I'm just going off some info I found online.  The first time I had to bleed the system to get the oil running it took me hours of research for what turned out to be a 5 minute job.

Got the info from this site - https://www.nihe.gov.uk/index/advice/maintaining_your_home/winter_maintenance/water_supply.htm

In which case I would leave it to a plumber/heating engineer to sort out if I were you. 

That was my conclusion too. Just wasn't sure if it was worth seeing if the heating guy could come out tomorrow but it looks like there's no point getting him out before the water is back on.

darthed1981

boogieman said:

RedRabbit said:

Cheers but I think I've managed to find the answer.

When the water leak started I turned the water off and turned the taps on until the ran dry.  In doing so I've emptied the cold water tank which is what the boiler feeds off to pump water around the radiators.  In the past when the water has gone off there's always been water in the tank which is why I've been able to keep the heating on.

Looks like I'm waiting until the plumber gets the water back on and see where we are then.

At least it's warmed up outside.

That sounds a very odd system indeed. The radiators in an open system shouldn’t be connected to the cold water tank (which you say you emptied when you turned on the taps) because there’s chemicals and hot water in the radiator system that shouldn’t get anywhere near your cold water tank. There should be a completely separate smaller feed and expansion tank that tops up your radiators. 

In our office we have a weird water header tank right above my servers!

It serves no real useful purpose, and I believe now we have our new boiler is in it is out of service, but it was weird it was even there.  At one point our HSQE Manager who got landed with building maintenance was going down manually filling it every week to ensure that the system didn't fill with air...

So maybe not a cold water tank per se but a header tank for the hot water system, where it is still cold?

Perdix

If you actually ran out of it can cause an air lock in the oil line. When the air reaches the burner it will shut down. The sir can sometimes take some shifting.

RedRabbit

Perdix said:

If you actually ran out of it can cause an air lock in the oil line. When the air reaches the burner it will shut down. The sir can sometimes take some shifting.

I've already bled the boiler as I was fairly sure there's be an air lock.  Came away with a rag soaked with kerosene so I think I've probably cleared it.

Either way it's beyond my skill set now.  I'll try firing it up once the water's back on but failing that it's time to call in the pros.

Nitefly

Don't forget to bleed the radiators once the water is back on...

strtdv

Is it a closed or open system? If it's an open system it's very odd that the water issue would affect the heating system as it has its own header tank, which unless you have a massive leak in the heating system shouldn't be emptying even if you drained your cold water tank (the two tanks shouldn't communicate at all as bacterial overgrowth is common in heating systems but is obviously something you really don't want in your cold water tank).
The heating system is fed from the water main separately to the cold water tank.

I'd have a look in your attic, and if there's water in the heating header tank then the water isn't your issue and you should look at the boiler again.

RedRabbit

strtdv said:

Is it a closed or open system? If it's an open system it's very odd that the water issue would affect the heating system as it has its own header tank, which unless you have a massive leak in the heating system shouldn't be emptying even if you drained your cold water tank (the two tanks shouldn't communicate at all as bacterial overgrowth is common in heating systems but is obviously something you really don't want in your cold water tank).
The heating system is fed from the water main separately to the cold water tank.

I'd have a look in your attic, and if there's water in the heating header tank then the water isn't your issue and you should look at the boiler again.

No idea.  I had assumed open system but that's only based on what my brother said and he admitted that he knew little more than me on these matters.

Just been into the loft - there are two tanks and a whole mess of pipes and pumps that I couldn't really follow too well.  The two tanks are a large one and a smaller one.  Based on how much water I ran off when the leak started I'm assuming the larger one will be the cold water tank and the smaller one the the header tank?

From what I could follow of the pipe work, water comes up from the pump outside the house (we're not on mains water - probably should have mentioned that) and is then split between the two tanks and the immersion heater (not on as it's expensive to run).  Other than that there's no link between the two tanks.

The larger one I couldn't see into as it's right up against the roof but a quick tap suggests it's completely empty.  The smaller one has some water in but not much.  I'm guessing it needs to top itself up (I've never had to do it manually) but can't as there's no water coming into the building.

As to why the system has drained - the bathroom radiator has a slow drip.  It's never been anything I was particularly worried about but maybe it could be enough over the course of the 6 days the water has been off to cause the heating system to lose pressure?

I'll mention all this to the plumber tomorrow.

RedRabbit

Nitefly said:

Don't forget to bleed the radiators once the water is back on...

Thank you.  I doubt this would have occurred to me.

boogieman

If there’s no water coming into the building then that’s the root of the problem and needs to be sorted first. 

As you say, the larger tank in the loft will be the cold water tank. That will normally just feed your bathroom cold tap, your hot water taps and toilet and doesn’t have anything to do with the C/H. You didn’t really need to empty that to work on the heating system. 

The small tank will be the feed and expansion tank for the C/H and should normally be at least half full. It should also have a ball cock inside the tank, same thing as in a toilet cistern: a valve with a float. This keeps the water level in the C/H system automatically topped up to the right amount. It may well be that if the C/H system has no water in it at all  (which it could be if there’s no water in the F&E tank) then the boiler is either a) seeing no water pressure or b) is shutting down on the overheat sensor. 

Anyway, I’d let the pros deal with the problems. Hope you get it sorted 

cacophony

very strange. for the heating header tank to be empty, your floor under the leaky radiator would be soaked. i would say that i would look at the water draining out of the tank back down the supply pipe now that the pressure has gone , but that would be impossible if the system was up to anything like modern standards, with a backcheck valve and the feed being in to the top of the tank.

boogieman

cacophony said:

very strange. for the heating header tank to be empty, your floor under the leaky radiator would be soaked. i would say that i would look at the water draining out of the tank back down the supply pipe now that the pressure has gone , but that would be impossible if the system was up to anything like modern standards, with a backcheck valve and the feed being in to the top of the tank.

I had an ancient Servowarm system in my old house that didn’t have a plumbed in supply to the F&E tank. It had to be topped up manually! If the OP has the same kind of thing then a slow leak in a rad would drain the system eventually.

It does sound an odd set up for the whole house though: presumably a pumped water supply not coming off the mains is supplied from a well? 

RedRabbit

The tank was emptied as I didn't know where the water leak was coming from and with water pissing down the bedroom wall at 3 in the morning I just turned off the stop tap and drained the pipes.

Not sure if there was a ball cock in the smaller tank - again it's up close to the roof so I could only lift the top and peak in.

The only warning light on the boiler is the lock out light which comes on if there's no oil reaching the burner but hasn't come on now there's a full tank of oil.  There's just no flame and the radiators aren't heating up.

The drip on the radiator is very slow - maybe a drop every few minutes.  With the heating off there's a small puddle under it and the towel that's draped over it has a small wet patch where it comes into contact with the drip.  I wouldn't think it's enough to have drained the system but maybe just enough to lose pressure?  The header/feed tank is pretty small.  I doubt it's more than a gallon.

I don't know and am just guessing at this point.