Increasing pressure to gas boiler

DublinWriter

Our gas boiler won't spark anymore because the water pressure from the attic tank has gone to just under 1bar (says so on the boiler guage).

Had a plumber around to look at it and he recommended taking a feed from the fresh water at ground level (higher pressure).

Personally, I would have thought that either putting wider pipes down from the attic (I think they are only 1/4 inch, so not enough water in the pipe to have enough pressure to gravity feed) or installing a pump in the attic would have been the better options.

Opinions anyone?

Lemo

Not an expert at all on this but if it's a sealed system then the pressure loss means the system has lost water somewhere. My sealed system is fed from the cold water tank via a valve which I open to top up whenever the pressue drops.

Where are you based? My experience is that some plumbers don't understand much about water and pressure :-) I had one who told me that water could not travel upwards! A guy in Swords eventually sorted out my previously troublesome system. PM me if you want a number.

DublinWriter

Lemo wrote:

Not an expert at all on this but if it's a sealed system then the pressure loss means the system has lost water somewhere. My sealed system is fed from the cold water tank via a valve which I open to top up whenever the pressue drops.

Where are you based? My experience is that some plumbers don't understand much about water and pressure :-) I had one who told me that water could not travel upwards! A guy in Swords eventually sorted out my previously troublesome system. PM me if you want a number.

Thanks, will PM you!

The pressure was always low because of the pipes being too narrow coming down from the attic tank. It was always on the 1bar cut off line. Plus the rads heat up when I put the switch onto the 'Hot Water' position only, so it's a lot of a mess really.

I'm based in Duleek, Co. Meath, Swords is about 45 minutes away.

Endymion

DublinWriter wrote:

Our gas boiler won't spark anymore because the water pressure from the attic tank has gone to just under 1bar (says so on the boiler guage).

have to agree with Leno here, sounds like your plumber doesn't know much about pressure. If your gas pressure was low, you boiler might not spark, however if your water pressure is too low, you boiler will come on, and go off very quickly, since the pressure isn't high enough to move the heated water away from the boiler quickly, the boiler thinks it's reached to cut off temp, and shut down.

Water pressure problems in closed systems are usually linked to the water pump. You water pump will be close to your boiler, their usually a kinda red colour. Right in the centre theres a screw air fitting thing, open it up, it can be used to release trapped air and you will be able to see the pump working.

btw, if your pump is off (which it should be if your boiler is off) you water pressure will could easily be below 1bar. This doesn't indicate a problem.

All the above said, if your boiler is miss sparking, it sound like a poor gas supply causing either low pressure, or a small bit of dirt in the feed. I'd get your boiler serviced by a central heating professional, rather then looking to a plumber.

Reyman

What kind of plumber put in a 1/4" feed from the attic tank?

That sounds very strange - have you had it checked?

DublinWriter

Reyman wrote:

What kind of plumber put in a 1/4" feed from the attic tank?

The same kind of plumber that failed to put an isolation valve on the boiler in the first place, meaning that it couldn't be serviced.

The same kind of plumber that rigged the system so that in order to have hot water, I have to set the thermostat in the hall to 30oC or the boiler won't spark, even with the Hot Water/Rads switch set to the Hot Water position (and the rads still get hot!).

Thankfully, I got the builder get the original plumber in to put the valve on the boiler so it could be serviced. When the gas technician came back there was a bit of dirt in one of the valves in the boiler which he cleaned out and all worked well for a while, but he mentioned that the pressure was barely above one bar and that the boiler might not fire in the future if the water pressure went down.

There isn't a pump anywhere in equation, so that's why I was thinking that if I had a pump in the attic it would solve all the problems.

The boiler was only serviced about six months ago, as I've been using the immersion. But winter is coming!

Reyman

DublinWriter wrote:

There isn't a pump anywhere in equation, so that's why I was thinking that if I had a pump in the attic it would solve all the problems.

!

I'm missing something here. How do you mean ' there's no pump in the equation' ?
How is the water being moved around the radiators/ cylinder heat exchanger?

Endymion

Reyman wrote:

I'm missing something here. How do you mean ' there's no pump in the equation' ?
How is the water being moved around the radiators/ cylinder heat exchanger?

exactly what I'm thinking. There has to be a pump somewhere.

but he mentioned that the pressure was barely above one bar and that the boiler might not fire in the future if the water pressure went down.

I suppose, if it has a built in barometer, it might not fire if the pressure is too low, however, usually it like I discribed above, comes on and goes off very quickly.

It's bad if its been service six months ago and the problem is back, but again, your problem is most likely still dirt in the gas supply.

Ps, what do you mean by an isolation valve? You mean for the gas? Surely that was the heating guys job to install? Or where they one and the same person?

DublinWriter

Carnivore wrote:

exactly what I'm thinking. There has to be a pump somewhere.

There has to be a pump in the boiler unit I'd imagine. But I'm talking about an external pump to pump water to the boiler to increase the low pressure from the attic.

Carnivore wrote:

Ps, what do you mean by an isolation valve? You mean for the gas? Surely that was the heating guys job to install? Or where they one and the same person?

There was no valve fitted on the feeding pipe to shut off the water going into the boiler.

Endymion

DublinWriter wrote:

There has to be a pump in the boiler unit I'd imagine. But I'm talking about an external pump to pump water to the boiler to increase the low pressure from the attic.

Theres no pump in the boiler itself, well I've never seen one inside a domestic gas boiler. You have to have an external one somewhere. If you have poor water pressure its probably down to that. It might not be strong enough, or it might be broken.

There was no valve fitted on the feeding pipe to shut off the water going into the boiler.

valve is probably near your pump. Some carpenter could have boxer it all in.

Reyman

It seems to me that you may have a problem with this circulating pump i.e. it may not be moving water around the system and hence the boiler is turning off because the water close to it is overheating.

Have you checked the pump is working ? If it is, there's often several settings on it (1-3) that you can adjust with a screwdriver and raise or lower the pressure. This might solve your problem.

I certainly wouldn't use another pump to raise the water pressure from the attic. I've never heard of this being done. The attic supply should only be providing water on rare occasions when the system leaks a little or loses a small amount of water.
Fresh water cannot be introduced continuously to a heating system or the radiators and boiler will corrode due to electrolytic action. The system is by definition 'closed'

DublinWriter

Carnivore wrote:

valve is probably near your pump. Some carpenter could have boxer it all in.

Nope. Had two engineers out, one from Bord Gas and the other from BrightGas in Drogheda who both said "there's no isolation valve on your boiler, we cannot service it".

Called the original builder, he got the original plumber out to put on the required valve, Brightgas came out, serviced the unit, and all was well for six months.

Basically I think it's an issue with pressure now, or more dirt building up.

Either way, when I switched the boiler on for just hot water, the rads heated up. So something is wrong!

Viking House

I agree with the plumber who told you to connect your boiler to the mains to increase the pressure, we do it all the time.

Endymion

Reyman wrote:

Fresh water cannot be introduced continuously to a heating system or the radiators and boiler will corrode due to electrolytic action. The system is by definition 'closed'

viking house, did you even read the above

dublinwriter. A tank, will have higher pressure then mains. The tank is only used to top up your central heating system. connecting the mains to the boiler is a real cowboy job.

Viking House

Hi Carnivore

How were you going to increase the pressure in his closed system to get it working? by first letting water into a tank in the attic where it somehow becomes unfresh and gravity feeding it into the closed boiler/radiator loop.
Where were you going to get water without oxygen to put into the radiator system that will not corrode the rads?

We always fit Condensing Combi boilers to renovations and new builds. These systems have no tanks in the attic or copper cylinders. We always connect the closed loop to the mains water with a penny valve near the boiler for pressurising the system.
This system is about twice as efficient as the regular tank in the attic system.

Now I've got to go outside and water my horse!!

Reyman

Are we sure this is a 'sealed' system i.e. not using the attic tank to top for water losses?

Maybe the OP could confirm?

Endymion

Viking House wrote:

Hi Carnivore

How were you going to increase the pressure in his closed system to get it working? by first letting water into a tank in the attic where it somehow becomes unfresh and gravity feeding it into the closed boiler/radiator loop.
Where were you going to get water without oxygen to put into the radiator system that will not corrode the rads?

We always fit Condensing Combi boilers to renovations and new builds. These systems have no tanks in the attic or copper cylinders. We always connect the closed loop to the mains water with a penny valve near the boiler for pressurising the system.
This system is about twice as efficient as the regular tank in the attic system.

Now I've got to go outside and water my horse!!

Personally I still think his pressure problem is with his pump, which he says doesn't exist. If the pump is broken, or not strong enough, I'd buy a new one, before I'd go replumbing.

secondly, you never said you where talking about a condensing combi boiler, I persumed it was a traditional storage system. I retract the cowboy comment and appologise. However I stand by what reymen said, continusously feeding fresh water into a traditional system would be a mistake.

311

Sorry for coming in late to this thread ,
I cannot for the life of me understand what the issue about isolating the boiler is .
The type of boilers that have this feature of the boiler shutting down ,come with isolating valves at the bottom ,they are part of the boiler.
What model of boiler is it ,baxi ? ,vokera ?.....

Pressure loss can be caused by leakage ,or the boiler overheating and the safety valve opening. Again ,its strange that 1bar is needed ,very seldom will you get 1bar from a tank in an attic ,if you are lucky in a big house youll get half a bar because the tank is higher up. You are not suppose to connect a boiler to the mains supply unless you have to.

EDIT : Ask the next person ,or builder,plumber to tell you where the Non Return Valve is . Locate the non return valve ,have it pointed out to you or have the plumber tell you where it is over the phone.
Without a non return valve on the system ,your system is not installed properly and will get the boiler so dirty that the guarantee will be invalid.

Endymion

Something just occured to me, if the guy had a combi boiler, he would allready have a mains connection to his boiler, and regardless of what type of boiler, the central heating part of it should be topped up via an attic tank and a pressure valve. Having thought on it, I fail to see how topping up your closed system from the mains has any benefit over a tank. and I know most plumbers will use a tank. I can only persume that stagnent tank water somehow releases it ******, but I don't know.

I honestly dont see what it is about a combi boiler, which makes you think it is ok to top it up from the mains. I still think its a cheap way of doing it, rather then it having any benifits.

311

A heating system works better with a bit of pressure inside ,also mains pressure can get rid of any little air locks around the heating system.
I'll often have to backfill a heating system to get rid of an air lock ,can happen when you alter an old heating system.

DublinWriter

_Brian_ wrote:

Sorry for coming in late to this thread ,
I cannot for the life of me understand what the issue about isolating the boiler is .
The type of boilers that have this feature of the boiler shutting down ,come with isolating valves at the bottom ,they are part of the boiler.
What model of boiler is it ,baxi ? ,vokera ?.....

Well, as I said, both engineers wouldn't touch it until the valve was installed.

The make of the Boiler is 'Luna' (Spanish).

But I think I'm using the word 'valve' a little free and loose here - apologies for my ignorance.

What needed to be installed was a cut off on pipe feeding the water to the boiler.

Reyman

_Brian_ wrote:

...

Again ,its strange that 1bar is needed ,very seldom will you get 1bar from a tank in an attic ,if you are lucky in a big house youll get half a bar because the tank is higher up.

From my memory 1 bar is approximately 1 atmosphere or sufficient to support a column of water 30' high. This means you would need a head of 30' to get 1 bar at your boiler. If it's a two storey house you are probably getting around 15' from the attic to a few feet from the ceiling of the ground floor (where the boiler is). This works out at 0.5 bar, which is what you're reading. The 1/4 inch pipe dimension will have no effect on the pressure reading. It will only affect the rate of water flow to the boiler.

DublinWriter

Reyman wrote:

The 1/4 inch pipe dimension will have no effect on the pressure reading. It will only affect the rate of water flow to the boiler.

Hmmm, are you sure?

Surely the greater volume of water sitting in the downward pipe the greater the pressure at the end of the pipe?

Reyman

Certain - basic physics. Pressure results from the head in feet not the inside pipe surface area.

Now the flow rate - that's a different matter. Then the pipe dimensions come into play

311

Reyman wrote:

From my memory 1 bar is approximately 1 atmosphere or sufficient to support a column of water 30' high. This means you would need a head of 30' to get 1 bar at your boiler. If it's a two storey house you are probably getting around 15' from the attic to a few feet from the ceiling of the ground floor (where the boiler is). This works out at 0.5 bar, which is what you're reading. The 1/4 inch pipe dimension will have no effect on the pressure reading. It will only affect the rate of water flow to the boiler.

I do calls for the gas company ,fix boilers and make installations safe that are not done properly by bogus installers ,the only dealings I have with atmospheres is a good house party every now and then .

Brian.

311

DublinWriter wrote:

Well, as I said, both engineers wouldn't touch it until the valve was installed.

The make of the Boiler is 'Luna' (Spanish).

But I think I'm using the word 'valve' a little free and loose here - apologies for my ignorance.

What needed to be installed was a cut off on pipe feeding the water to the boiler.

I'm not familiar with that brand ,a lot of these boilers are rebadged italian boilers.
How old is the boiler ,normally theres a service engineer available from the boiler manufacturer. If I or any bord Gais installer has a problem with the boiler in the first year ,I can have a technician from the manufacturer out in 24hours.