Glowworm 18si pump housing ?

[barry11]

Hi all,
My boiler is a gloworm 18si it is running 8 rads in a normal 3 bed semi.
I have had nothing but a headache with this boiler from day one.
I think i have narrowed the problem down to the pump housing and i am looking for opinions.
Fistly the rads were only heating upstairs downstairs were luke warm.
went through taking rads off walls flushing them with a hose.
Problem solved for a couple of days "rads hoping hot" after a couple of days it takes longer for the rads to heat.After a week or so take about an hour but tempeture not high.
I decided to check a filter that is located in the pump housing beside the drain valve.
First i drained the boiler down with the drain valve untill no more came out
then i opened the bleed screw on the rad in the upstairs bathroom and a bit more came out.
Then i pulled the filter and boy did i get wet.
I replaced the filter with a new one and away the heating was again "that good i had to turn the tempeture down"
Now three weeks later the heating is after dipping again tempeture low taking a long time to heat.
So i decided to pull the filter again and wash it out,put it back in and heating working great again.
My question is could this pump housing have a crack and letting air into the system and there for causing an air lock in the housing ?
The pump it self is working fine.
The reason i suspect this is because air is getting into the system at a rapid pace and the rad in the upstairs bathroom is functioning like an expansion vesel for the system.
Tomorrow i will have to bleed air from this rad and refill the lost pressure.
There is no leaks as far as i can tell as this has been going on a long time and no sign of water anywhere in the house.
This boiler has an expansion vessel at the back of the boiler and no more on the system.
OPINIONS ON THIS PLEASE.

 

[jackthom]

Just to cover all possibilities, is there definitely plenty of inhibitor in the system water?

The gas causing the airlocks may not be air.

 

[barry11]

Just to cover all possibilities, is there definitely plenty of inhibitor in the system water?

The gas causing the airlocks may not be air.

I am not to sure if there ever was any put in.The house is four years old and maybe you are right.When i bleed the rad it has a strong smell.

 

[jackthom]

probably been bled and refilled with only fresh water since it was installed.

You should add something like this via a partially drained radiator or filling loop.

http://www.screwfix.com/prods/75330...ox-Superconcentrate-Central-Heating-Protector

 

[barry11]

Thanks jackthom.
I have went and bought some inhibitor today and i also bought some cleaning agent.
The problem I have now is I have put the cleaner in the small rad in the upstairs bathroom.
I took the rad off the wall and poured the cleaner in..and refilled IS THIS OK
Now the problem.
There is no area on the system to completly drain the system down(DRAIN VALVE).I also know i will have to run the cleaner for a couple of weeks.
So my idea to drain would be to remove the pipe entering to rad in the sitting room (AND DRAIN THE SYSTEM FROM THERE) would this be the correct thing to do as this is the lowest point and the farest point from the boiler.
Also 1 last qusetion do i leave the boiler (NOT DRAIN) and let all the water drain from the pipe in the sitting room ?

 

[jackthom]

That sounds OK.

Draining at the lowest point is good but you can also drain in turn from other points too if you think that will get more dirty water out of the system. Opening bleed valves will help speed up the last dregs.

I would be inclined to refill the system, run the heating for a while and drain again, a couple of times to get the last trace of cleaner out.

 

[barry11]

I have done all that but today the system start gurgling (boiling) over.
seems there is an air blockage and a slight howling noise any ideas about this.
Also should this system only have one expansion tank which is located at the back of the boiler.
Would it not make sence to have one higher than the boiler as air rises ?
I am on here to learn so any help would be great.
Also it looks like i am going to have to drain down the boiler again to get rid of the air lock.
Upstairs rads heating fine but downstairs is no heat at all now.
It making noises that is not for the faint hearted.
In my hotpress upstairs there is an outlet point for air but only venting a tiny bit of air ? could i fit an expansion tank to this pipe and remove the vent as the boiler also vent air.but it seems these vents only vents when the pressure gets very high.

Any Info Would Be Great

 

[barry11]

Problem Half solved,
I let the boiler fill up and over pressure and removed the clip off the filter which is located on the pump housing.
Left the system pressure build up and the filter poped out under the water pressure (with a lot of dirt or corrosion).
I have done this about 10 times each time getting a little more dirt
I then refilled the system bleed the rads and fired up.
Heating all rads in the house to a good tempeture except 1.
This one is stone cold including the inlet and outlet pipe.
Seems the problems i am having are as Jackthom suggested that no inhibitor was present in the system which caused some corrosion.
Any suggestions why this 1 rad is not working ? (BLOCKAGE MAYBE)
Would a powerflush be called for ?
Also maybe a magnaclean fitted?

 

[jackthom]

You may get the troublesome radiator going by turning off all the others and getting the full force of the pump to encourage it to start.

Once you get a bit of flow throughout the system the cleaning additive can gradually do its job. It obviously won't do any good in areas where there's no circulation.

 

[mickyg]

there's another more common place to check for blockages on your boiler. Where the pipe comes on the return from the heat exchanger it connects into a plastic hydroblock on the LHS. There is 2 brass fittings at opposite ends of the block, this is where a diverter valve would go in the combi version. Trouble is, half the diverter cartridge is left inside even on the system version. You can get a build up of crud in here, so remove the 2 brass ends and clean out what you can. Remove the pin and spring from inside as you don't need these and just replace the 2 brass ends, leaving the waterway clear of obstroctions.

 

[barry11]

Thanks mickyg,
Have you got any idea why i am getting a pressure drop when this system cools down?
Pressure will stay good as long as the boiler is running.I could run it for as long as i want without it dropping.
But if i switch it off and let it cool the pressure is dropping.
I am 99% sure there is no leaks in the system.
boiler was running yesterday and i switched it across to check the pressure it was at 1.1 bar after filling it to 1 bar.
This morning first thing i checked the pressure and it 0.7 bar so i bleed the small rad in the bathroom and filled the system back to 1 bar.
It seems to me that this small rad is acting like an expansion tank.
Any ideas what would be happening with the pressure.

Maybe expansion vessel needs pumping and i have no idea of where the valve is to do this.
The boiler is in a fairly tight area i can get the right hand side panel off but there is no room for the left side to come off.Otherwise half the kitchen units will have to come down
Can you explain where this valve is on my system ?
The only thing i can see is a flexable pipe going to the bottom of the expansion vessel

If this cannot be pumped or has failed
Can i add another expansion vessel to this system in my hotpress to take the place of the one thats fitted behind the boiler ?
If i can explain my thinking behind this.....
If the rad in the bathroom upstairs acts like an expansion tank.
I could add an expansion tank upstairs which will give the expanding air a place to go.
If this tank is higher than the higest rad the water level should remain good in the system.

The other side of this is.Where is the lost water going ?
The srv pipe outside is bone dry there is cobwebs over it.
and there is no signs of any leaks around the house.

On the manual it showes another expansion vessel fitted if required.

Opinions please...

 

[jackthom]

I suspect your expansion vessel is doing its job OK. The extra gas building up in one radiator wouldn't take the pressure off the system, it would actually make things worse if the main vessel wasn't giving the displaced water somewhere to go.

You may well have a leak somewhere though and Pressure Release Valves are notorious for this.

 

[barry11]

I switched off the Boiler
Over the past hour there has been a .03 bar drop.And i have checked the SRV (bone dry)
Defo not leaking there.
Is there any way of checking for leaks without ripping floorboards up and tearing plasterboard walls apart ?
Is there common places where leaks tend to show up ?

 

[barry11]

AS above and also i am still looking for the general area of the valve on the expansion vessel so i can check the pressure.

 

[barry11]

bump