Downstairs hot water part-blockage


19 Oct 2010
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United Kingdom
I have a gravity fed indirect central heating/hot water system. A new probem has just arisen. Upstairs hot water (bathroom & shower room) is fine. Downstairs hot water is just a trickle. I have connected the mains cold water to the downstairs hot water for about a minute and this temporarily clears the problem - sometimes for several days, sometimes for a couple of hours.
Is it safe to run the mains cold water for a longer period or will I risk moving the blockage to the upstairs bathroom ? Is there another way to remove the blockage, which is probably grit from a shower installed 5 years ago?
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See if you can disconnect the hot pipework to the kitchen tap and flush it through properly.
If you are handy with pipework then cut the supply to the hot tap and fit some pipework to outside and let it flush through with mains water. Choose a day when you are not going to need your CH or hot water. :D
1. how did grit get in when fitting the shower
2. how has it taken 5 years to arise as a problem
3. have you drained the hot water system for any reason
4. is there a shower pump on the system
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to Shorky -
1. I had the shower fitted 5 yrs ago by a "friend" - not a professional. I am only guessing that my friend carelessly let a lump of grit get in because there have often been some hot water pressure problems in the shower starting 2 years after the installation

2. I imagine that the grit has worked its way down the hot water pipe. Maybe it got stuck near the shower then moved and has got stuck again. the shower is working normally.

3. Never drained the H/W system

4. No shower pump. The shower was designed for gravity feed.

I asked a plumber, and he had no idea other than taking up floorboards to look, which sounds expensive. So I'd be grateful for any advice. many thanks

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