low hot water pressure All aspects of plumbing questions and answers, help, tips and information

[jennyb]

Have ridiculously low pressure from hot tap in bath-dribbles out when tap on fully-bathroom sink and kitchen sink not too bad. Have combi boiler apparently cold running from tank in loft and hot from mains??? Want to install a shower but no point if pressure remains poor. Any ideas?

[DONFRAMAC]

Combi's not known for generous flow, but sometimes the bath supply is impaired by excessive pressure ;-- nipping the valve supplying the combi can help a little, but the best flow you can hope for is what you have at the basin in the bathroom. If the feed from the tank to the bathroom is only 15 mm you may get a little more by uprating to the old standard 22 mm, as far as the bath hot tap.
For a decent shower flow, you need to be thinking of a high KW electric unit, from the rising-main, or from the loft header if you choose pump-assist.