Plumbing & Plumbers Forum - On/Off H/W in bath & shower
On/Off H/W in bath & shower
Discuss On/Off H/W in bath & shower in the Central Heating Forum at Plumbers Forums; My old dear's friend wants me to go and have a look at her bath/shower as she's getting hot/cold/hot/cold upstairs but the hot flow is fine downstairs.
Sounds to me ...
Coincidentally, I posted this somewhere else earlier today.
It's not exactly the same problem, but might be the solution.
You'll need a water pressure gauge to measure the water pressure and a weir gauge to measure the water flow.
From earlier today ...
Just returned from a house where hot water flow is poor. They have a fairly large combi boiler but since installation (by other plumbers) the bath has taken ages to fill although central heating is fine.
Looking in the boiler the plate heat exchanger has corroded and water is leaking everywhere.
Before automatically fitting a new one, I felt some testing was required:
Mains water pressure is 3.8 bar. Water flow rate around 18 litres per minute. So far so good.
Hot water flow rate is 6 litres per minute (everywhere, not just bath).
Contacted manufacturers who confirmed my suspicions. They need a pressure reducing valve to reduce water pressure to 2 bar before it enters the boiler. Then when done, I can change old heat exchanger and service the boiler. The manufacturers tell me this should sort out the hot water flow as the boiler can cope with 2 bar but not with 3.8 bar and, presumably, will create the hot water flow as required.
As I said earlier, hope this helps.
Last edited by dontknowitall; 20-08-2009 at 06:25 PM.
Reason: Reference to a pump irrelevant to this thread