Hot Water pressure - or lack of it

[alexbartman]

Hi

I have a fairly standard Gravity-fed vented system in a fairly standar two-storey house. I have just re-done my kitchen and replaced the tap with a funky new monobloc (ceramic valve) mixer.

As a result, the hW pressure through this tap is really low and wit the mains pressure feed for the Cold Water, the tap temparature i either freezing cold and very powerful or boiling hot and v slow there's no "mixing" of hot and cold. I've tried closing the servic valve for the CW a little and this works, but it's not great a mixing. I was thinking of adding a HW pump in the loft from the cylinder, bu my mixer shower in the upstairs bathroom already has a pump attached t boost the tank-fed Hot and Cold feeds. I have another shower that is power shower that also relies on tank-fed low pressure hot and col feeds. Access in my new kitchen it very limited, has anyone any suggestions a to how I can boost the pressure for the kitchen tap?? Overall pressure of the hot taps in the bathrooms(s) is not great - bu not as important as the kitchen for washing-up etc etc.

Thanks in advance for help and advice

Ale

-- alexbartman

[alexbartman]

can anyone help????!

-- alexbartman

[Roger Mills (aka Set Square)]

The best bet is probably yet another pump, in the pipe which feeds just the kitchen tap - so you'll need to trace the route, and find the most suitable place to put it. That's unlikely to be in the attic - unless the hot tank is in the attic, and there's a dedicated feed to the kitchen tap from it.

Another alternative is to make use of the existing shower pump. In this case, you would need to re-route the feed to the kitchen hot tap in such a way that it connects on the shower side of this pump rather than wherever it's fed from at present. Not sure what happens if you take just a hot feed from the pump - so that the cold side runs stalled - but it may not be too disastrous. It would do that anyway if you used the shower on full hot.

If you take this route, you'll need to make sure that any flow switch which switches on the shower pump does so by sensing the *hot* flow rather than the cold.

[timegoesby]

The simplest is to fit a Grundfos Booster pump on the hot water line. This is like a normal CH pump with 1/2" connections and can be fitted under the sink or at the cylinder. You have a few showers and high pressure mixing. All you will be doing is Heath Robinson the water system as you add things to it. It may be the time to stand back rethink and save space into the deal, which you seem to value. If your water mains are up to it, I would consider a high flow rate combi or heat bank. a new condensing combi boiler will also drop the gas bills as well.

[Dave Plowman (News)]

I recently - like the OP - changed my ancient kitchen mixer to one of those flash 1/4 turn types. It had the old 'standard' 1/2 inputs so I assumed it was fine for a low pressure hot water system. And I was wrong. The previous mixer had ordinary taps and the hot water flow was near the same as the cold - my mains water pressure isn't high. The new one has cut it to an annoyingly low flow.

So - are there any modern mixers which work well on low pressure or do I get a pump?

I'm not sure I want to pump the entire system as my shower works perfectly as do all other hot taps. So do they make a 15mm version I could just fit in the kitchen - or use reducers?

[Doctor Drivel]

You need to rip out the tanks and cylinder and fit a high flowrate combi ASAP.

[alexbartman]

It is almost time to replace my ancient boiler - but it will be a ver great shame to have to ruin my lovely bathroom(s) to remove pump etc.......dont suppose there is any way round it though. My previou experiences of a COmbi in my last houe was not great the pressure i the mixer shower was far from great - despite having mains pressure i the bathroom.....

-- alexbartman

[Doctor Drivel]

Either poor mains pressure or poor mixer. Combis selling point is the brilliant showers.

[Andy Hall]

Three alternatives spring to mind:

- Hot water pump as you suggest

- Under sink electric water heater run from mains.

- Change to mains hot water system (.e.g. combi boiler or heatbank.)