Perplexing heating / water problem

[kevplumb]

It's pumping down.

I've also go the book for the pump (a Grundfos UPS) it says that pumping downwards in a vertical pipe is acceptable but not recommended.

tryed that one chris

 

[croydoncorgi]

"Pump in the worse possible position sucking out from the least line of resistance, the top of the boiler, "

but it isn't, it's pumping towards the boiler.

Are you sure?
If the pump head is in the 'usual' orientation as it comes from the factory, then it's pumping DOWNWARDS. Not possible to read the arrow on the body (not enough pixcels!) but the casting shape looks right for downwards.

 

[doitall]

Lets get one thing quite clear, if the arrow is facing towards to boiler then its installed wrong.

Chris's theory with the cold feed is also wrong, as a blocked or restricted cold feed would suck air not blow water.

 

[doitall]

"Pump in the worse possible position sucking out from the least line of resistance, the top of the boiler, "

but it isn't, it's pumping towards the boiler.

Are you sure?
If the pump head is in the 'usual' orientation as it comes from the factory, then it's pumping DOWNWARDS. Not possible to read the arrow on the body (not enough pixcels!) but the casting shape looks right for downwards.

Yes curly thats what I said the flow is connected to the top of the boiler and the pump is in the flow facing downhill

And I got a rotten cold so don't annoy me

 

[Noraslad]

curly never said jack sh*t, don't do heating, but as an observation, pump looks pretty new to me, are you sure someone just didn't put it in wrong way round

 

[doitall]

curly never said jack sh*t, don't do heating, but as an observation, pump looks pretty new to me, are you sure someone just didn't put it in wrong way round

Oooooooooooooooopps

 

[ChrisR]

Quote:
"Pump in the worse possible position sucking out from the least line of resistance, the top of the boiler, "

but it isn't, it's pumping towards the boiler.

Yes, sorry I got that wrong, but the rest holds.
By the way the 2-port valves are also in the correct way round if the pump is pumping downwards.

If the pump's in backwards - everyone's first thought - then sure it could pump over. But we have it from a guy who sounds like he can read an arrow that it isn't!

Pump pumping downwards is not a problem except for bleeding. Millions of them are fitted pumping down

Chris's theory with the cold feed is also wrong, as a blocked or restricted cold feed would suck air not blow water.

Nonsense! " A blocked feed would blow water " ?? In my experience blocked pipes do not suck.
And if the feed pipe were blocked completely there would be no blowing anything because water can't get in!


Now look here chaps, we all know the only way you're gonna get water going out of the vent is if the pressure at the bottom of the vent is higher than that at the bottom of the feed. With them connected where they are, if there was a resistance between them, say in the pipe between the return pipe at the point where the feed joins, it and the boiler, the water in the FEED pipe would rise.

So either the pump's in backwards, which means the guy's blind, or there's another mechanism at work.
The pipe layout with respect to the boiler is perfectly ordinary. the venturi thing is quite well known enough to have been in the boards, and scale is often involved because it causes increases in water velocity in a way which creates disproportionate decreases in pressure - and usually somewhere round the base of the feed pipe.

 

[doitall]

hello chris sorry I couldn't make it, got a real stinker, next week ok.

Check the vent and cold feed for any tees off, towel rail circuit etc.

For water to blow out the ventthere has to be a link between the cold feed and vent external of the boiler.

 

[ChrisR]

Yes that's a point you haven't got a loft conversion have you!!?

Aah poor dia. Go to bed with a Night Nurse.

 

[kevplumb]

if he does the missus will slap him

still something niggling about that pump tho

 

[ChrisR]

They do a new bottle of medicine, might suit you Kev - Mental Nurse

 

[kevplumb]

 

[RedAl]

I'm pretty certain there are no connections to the vent or feed pipe other that those shown in the pictures. They are boxed in outside the wall so i'll lever the cover off and check. They then go straight through the ceiling to the tank.

The pipes are pretty short as the tank is in the loftspace directly above the boiler. There is no first floor above the boiler.

What is the minimum height the f/e tank needs to be above the highest radiator ? The only unusual thing I can see about the installation is that there are a couple of first floor radiators which would only be about 1M below the f/e tank.

 

[doitall]

The pipe you call the vent shown on the right hand side of the boiler, if there's any connection in it then that is the problem so check from the boiler to where it goes over the tank.

 

[doitall]

Chris,

Theres a night porter in the hotel, will that do