I have installed a new mixer tap in my kitchen (Monaco Pull Out Tap Chrome Finish) but since I have installed it I have lost pressure when in hot and takes longer to heat up, sure there are no blockages but have a feeling it is the tap or hose that is not compatible for "low pressure"?
The cold feed is direct from mains and the hot is gravity from hot water cylinder in cupboard upstairs

How was the hot pressure with the old faucet? You may have a clogged hot inlet on the new faucet. Model name or number would be helpful. Is this your faucet Monaco Pull Out Tap Chrome Finish, 8000177120190 (http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9996569)

What kind of faucet did you have before? Was it two knobs with a single spout or was it two completely separate taps?

1. I have no blockages, I am assuming that it is a tap that is not compatible with "low pressure" systems, i.e. no "pressure equaliser"? Is there such taps?

2. It was a 2 tap mixer (single spout)

3. Yes Ballengerb1 it is that very tap!

Can you find out what pressure is in your pipes?

Not sure how to find out pressure, not got the tool to do so either! Are there taps that just are not compatible for low pressure?

Testing water pressure is easier than installing that faucet, who install it? Attach a simple gauge to you outside spigot and open the spigot, hoping for 40-45 psi. Campbell BTG0-100 3/4 in F Hose Test Gauge (http://www.google.com/products/catalog?hl=en&q=gauge+to+test+water+pressure&wrapid=tlif129632194261010&um=1&ie=UTF-8&cid=17809193206665294135&ei=n01ETfLXFoS0lQfH750z&sa=X&oi=product_catalog_result&ct=result&resnum=4&ved=0CEkQ8wIwAw#)

If the old faucet was a two handle or knob with a single spout the new faucet should work. However, it may not if the new faucet is a single lever, since this type usually employ a cartridge. The old one probably used compression stems and washers. Cartridges usually require a certain amount of water pressure to operate properly.

Bob,
Note that the hot is a gravity fed line from an upper level. Cold is pressure fed from house main.

Rixie,

After having pulled up that model faucet, I don't think you will be able to make it work, for reason stated above.

You know sometimes people just don't read the question or even attempt to answer a question without sufficient know how. I have a similar problem which is caused by linking a High pressure requirement tap to a UK gravity fed hot water supply. Gravity fed water pressure has a dead easy calculation 00.1 bar per meter drop. Therefore if your hot tank is 5 metres away from the tap you only get 0.5bar pressure at the tap outlet. Fine for a standard 12.5mm internal pipe low pressure tap but blooming useless for a high pressure tap.
As I see it the only way round wanting to use a high pressure type tap in the kitchen sink is to fit into the hot water feed similar to a bathroom shower pump.
I am still trying to find out if my idea will work and is feasible, so watch this space.
Twodogs