Subject: Hot water system problem...
From: Andrew L VE_THIS_SPAM_STOPPERcom
Date: 08/09/04 09:09 GMT Daylight Time
Message-id:

Dear all,

I need some help diagnosing a problem I have with my hot water system.

I've got a cylinder tank in the airing cupboard which has above it two
square tanks, one large one small. I believe the larger is called the
feeder tank. As hot water is drained from the cylinder tank water is
drained from the feeder tank into they cylinder, which in turn is filled
up from the cold water mains supply up until a certain level (about a
1.5 inches below the overflow) at which point the float valve closes.

This all seems to work as described. If I don't use any hot water for
about 4 hours though the water level in the feeder tank has reached the
overflow and starts trickling out. It's a tiny, tiny trickle, so much so
that the water doesn't pour out of the end of overflow pipe but trickles
out the end, back along the bottom and is absorbed by the wall. The
plaster on that wall is blown. :-(

At first I thought that the float valve was shot, so I put in a
replacement, but that hasn't changed anything.

Any ideas as to what the problem might be, or what I should try next?

Many thanks

The overflow should vent outside and there should be enough downslope on it so
that water can't run back down the pipe. As to why the level rises there are a
couple of possibilities.

1) Hot water expands so you tend to find the level in the header tank rises a
bit anyway as the cylinder heats up. Set the float position lower. 3 or 4
inches below the overflow is about right. 1.5 is too close. If the float arm is
plastic there should be an adjusting screw on it and you just bend the brass
ones by hand.

2) If there is a steam vent pipe from the cylinder to the header tank does any
water trickle from that? A pump on too high a setting or a badly installed
system can lead to this.

--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)