hot water cylinder - pipework question ...

[steved101]

Hi

I am currently installing a new indirect hot water cylinder in my airing cupbaord (in bathroom). I hae had to alter the pipework slightly as the new cylinder flow, returrn and cold feed positions were slightly different, but my question is...

the cold feed should go into the cylinder at a very slight fall... but with mine, the pipe going into the cylinder (about 150mm long) doesn't stay at a fall !! this pipe goes to a tee, which then tees off to both the cold feed (from the cold tank_ and a drain valve is out of the other outlet. the cold feed pipe joins a gate valve about 4 feet up and then carries on to the tank. why does the pipe not stay at a slight fall when i leave it?!!

any help... should i be worried?

 

[gas4you]

Maybe it's because I've had an extremely stressful, bad and worthless day, but I find myself confused by your post.

I would not worry about this, if I read it right, as the pressure from the cold storage tank in your loft will overcome any slight run that does not fall.

 

[steved101]

Ok thanks mate. I was just worried about airlocks. Anyway, on tighetneing a bit more (the compression nut by the cylinder), the pipe stayed straight(er)! so maybe as the fittings were not tight the pipe kind of sagged/dipped a bit!

 

[Softus]

Don't rely on the strength of the cylinder to support the pipework.

CLIP IT!

 

[steved101]

pipework is clipped!!

dnt know why not going in at a fall though!

 

[Softus]

In that case I'm confused too.

The cold feed should be vertical, other than the stub as it enters the cylinder connection. If you're talking about a horizontal section in the loft, then you're right - this MUST have a fall to it or you will get air locking when filling, and poor flow the rest of the time.

For any cold feed with a horizontal section, I'd be inclined (no pun intended) to use 28mm pipework.

 

[steved101]

Hi there

the fall from the tank is at a slight fall, then a vertical drop (through the ceiling) and down. Then a gatev valve, then another vertical drop and a bend to a tee. this tee then goes horizontally into the cylinder, and a drain valve is from the other open end of the tee.

All i mean is that the small piece from the tee is not at a fall, just horizontal really (or even slightly (only v slightly) upwards)... and i don't know why?!! is it a big deal?

 

[gas4you]

You could have gentley bent the pipe to give a fall before joining it to the 22mm drop.

Quite often you have to slightly 'bend' these bits to where you want them, but ONLY slightly.

 

[kevplumb]

dave you missed out why are plumbers knees knackered

 

[namsag]

It will not make any difference at all so don`t worry about

 

[steved101]

the whole cold feed is in 22mm.

maybe it's just that i have overbend slightly y a few angles the bend, or that the connections are not fully tight (not finished at the mo)!


as said though, the pressure from the cold water tank in the loft should overcome any very slught horizontal/upward part. i was just worried about an airlock..

 

[Softus]

is it a big deal?

No.