Shower pressure drops

Schugeorge67

I have two showers in my house. **ALL heat and hot domestic water is provided by oil fired boiler** Only one shower can be used at a time or the pressure drops to a trickle. In fact if one is in use and hot water is turned ANYWHERE else in the house the same thing happens. There is a mixing valve in the system as well as a circ pump. Finally, the overalll pressure is slighter better in cold supply than hot water. Any ideas?

Jamie Hall

Well, the common factor is the mixing valve. So I'd start looking at it.

hot_rod

Check for plugged screens on the valves. Pressure reducing valves in the main water supply are a place to check, as well as the mixing valves

Mix valves could have a screen on hot and cold ports

A shut off valve that is not fully opened could be a cause also

PRR

> the overalll pressure is slighter better in cold supply than hot water.

Flow pressure is normally lower on hot because of the drag in the water heater.

Was it always like this or has it been going down for a while? If a screen fills-up slowly, you don't notice at first, but comes a day when ANY other load makes an intolerable drop.
Had a truck that would cruise to Maine but coffed on long hills. Had a brain-tickle. Blew out the fuel filter. Crud! With maybe 20% open area, it would cruise but not pull a hill. Had been driving the flatlands fine.

Big Ed_4

What kind of water heater , are you using the boiler coil pumping into a storage tank or is it piped as a extra zone piped to a tank . I am assuming you have a storage tank as you mentioned a circulator .If off the coil is there a check valve directing the incoming cold water though the coil ????