grant oil boiler

ltz400

I have a grant oil boiler that keep getting air lock ie water i have put in ds40 system cleaner in as there is a lot of black sludge on the boiler wont stay on any idea why.

DGOBS

Is the water pressure dropping, a leak maybe?
Why did you put in ds40, did you flush the system? did you properly neutralize after you finished?
DS40 can be extremely aggressive, and if you already had a pipework leak, it will possibly have made it worse

Why/how do you think it keeps air-locking? details please

ltz400

was told by the plumbing shop to use it i have neutralize it and flush the system.
plus have check for leaks and no sign

as for boiler it comes on heat up for while and then stops so am guesing its reached max temp limit on the boiler

shane0007

Sounds like a circulating pump issue combined with a sludge problem.

DGOBS

You sure your pump is circulating the water?

EURATS

ltz400 wrote: »

as for boiler it comes on heat up for while and then stops so am guesing its reached max temp limit on the boiler

Shouldn't reach max boiler temp..should reach temp set on thermo..and then knock off till system drops to lower set point and then come on again.

I had a similar problem before when I had the control unit off(no power to boiler either) for a period of time. Checked fuel filter and fuel tank. Used reset on boiler unit a couple of times. Reset(by killing power to and going through the setup process) the control unit a few times and I got it going.

ltz400

yes the pump is working or at lease it is making noise as eurats said it shouldnt reach max boiler temp but as u would think reach set temp is 75deg and after about 20minutes boiler will not come back on so i am lost if i open prv on the boiler some air comes and the same if i open the screw on the pump

DGOBS

Air or steam?
How old is the boiler

ltz400

it was air, it was put in late 80s

EURATS

ltz400 wrote: »

yes the pump is working or at lease it is making noise as eurats said it shouldnt reach max boiler temp but as u would think reach set temp is 75deg and after about 20minutes boiler will not come back on so i am lost if i open prv on the boiler some air comes and the same if i open the screw on the pump

Does the return get warm at all? Have recent experience of a pump that made noise..that when I opened it..was ceased/bolloxed.

Is there any water going into the expansion tank(i take it its an open system)from the ball cock? If there is a drip or worse..chances are u either have a leak or dodgy ball cock valve(dodgy valve wouldn't cause ur shutdown)

ltz400

yes the return get hot and it is open vented, no there is no water going into expansion tank

EURATS

ltz400 wrote: »

yes the return get hot and it is open vented, no there is no water going into expansion tank

If no water filling up the expansion..chances are u aren't loosing any. Hence no leak.

As I said before, I had an issue before with a control unit that I had to tinker with as the boiler kept knocking off after 20 seconds or so.

So your system is running for enough time to heat the system before it knocks off and then fails to restart..dodgy thermo?

ltz400

well if a thermo thats an easy fix also why is there water noise in the hallway rad when the pump comes on this pump is on a range

EURATS

ltz400 wrote: »

well if a thermo thats an easy fix also why is there water noise in the hallway rad when the pump comes on this pump is on a range

Yeah thermo handy if its the prob.
Water noise in hallway rad? Like water circulating or pissing out?

ltz400

its like water circulating but its loud

EURATS

ltz400 wrote: »

its like water circulating but its loud

So u have a dual system? Back boiler and oil/gas?

Is hard to say without having a look to be honest...not knowing where expansion, hot water cylinder and header tank are located relative to ur hallway. And also the pipes feeding them.

If ur system was caked with sh1te before..and ur circulation was crap..u prob would notice the water circulation sound now that it is running freely without the gunk.

ltz400

thks had a plumber round and he said that the pump is on the wrong pipe as its on the flow so plumber said that its pulling water out of the top of boiler and there would be steam at the top thats why thermo switches off boiler

Robbie.G

ltz400 wrote: »

thks had a plumber round and he said that the pump is on the wrong pipe as its on the flow so plumber said that its pulling water out of the top of boiler and there would be steam at the top thats why thermo switches off boiler

I don't agree with that there is no reason why the pump won't work on the flow sure grant show it in their installation manual.I am more drawn to the pump working to slow,causing poor return sludge build up or as simple as the stat not sitting into it phials correctly

shane0007

ltz400 wrote: »

thks had a plumber round and he said that the pump is on the wrong pipe as its on the flow so plumber said that its pulling water out of the top of boiler and there would be steam at the top thats why thermo switches off boiler

Nonsense. I am with Robbie on this one.

EURATS

shane0007 wrote: »

Nonsense. I am with Robbie on this one.

I would agree. Pump can go on flow or return.
How much did he charge to say that?

DGOBS

It doesn't matter, but is the pump in the right direction?
I came across one last year had been the wrong way round for 20 years, and the house took about an hour to heat up, the customer couldn't believe the difference once I reversed it

ltz400

a bit late in replying but got problem solved as i got a power flushing pump to flush it out and done it myself and oil boiler works great now,
so it would seem that sludge was the problem so thanks for all replys