Water heater outlet pipe conducting heat

Encrypted Pigeon

This may be obvious but I need to ask anyway. I had an electric hot water heater tank installed to heat a couple of sinks. The tank is located centrally with sinks a bit way (~8m away). The tank is one of those you would normally see under a sink (about 10L or so) as I wouldn't require alot. What I'm noticing now is the hot outlet pipe is getting hot and staying hot even when water is not been drawn. The obvious problem now I'm faced with is heat been wasted. Do these tanks not have any thermal insulator to stop the heat travelling out the hot pipe when not in use or, is this the expected behavior as they are normally meant to be near the sink? and if so, can you get some sort of insulator? or the bigger question, did I make the mistake of locating centrally as oppose to just putting one under each sink?

Encrypted Pigeon

Encrypted Pigeon wrote: »

This may be obvious but I need to ask anyway. I had an electric hot water heater tank installed to heat a couple of sinks. The tank is located centrally with sinks a bit way (~8m away). The tank is one of those you would normally see under a sink (about 10L or so) as I wouldn't require alot. What I'm noticing now is the hot outlet pipe is getting hot and staying hot even when water is not been drawn. The obvious problem now I'm faced with is heat been wasted. Do these tanks not have any thermal insulator to stop the heat travelling out the hot pipe when not in use or, is this the expected behavior as they are normally meant to be near the sink? and if so, can you get some sort of insulator? or the bigger question, did I make the mistake of locating centrally as oppose to just putting one under each sink?

They are under sink water heater and as such usually have very short draw offs.

There should be very little movement of heat up the outlet if the tap hasn't been opened.

Having a 8m draw off is very uneconomic and not practical with this type of water heater.

As these heater are rarely fitted taking in to account expansion of the mains water being heated you may find the standing pressure of the hot water is higher than the cold water, you can get movement of hot water to the tap as the hot and cold try to equalise across a mixing tap even if the tap is turned off.

Encrypted Pigeon

Thanks for the reply.

At the time, it was a gamble to try and nail two birds with one stone, I'm feeling the pinch now as it does require a bit of water waste/flow before the hot begins to come through.

So are you suggesting that its the heat of the expanded water I'm feeling on the outlet pipe? and not the tank itself trying to heat all the water in the tank as well as the water going to the tap?

If this is the case, ill live with it for a while, but I think ultimately Ill end up moving to a tank per sink.

corkgsxr

Put some armaflex insulation on it.

Wearb

Encrypted Pigeon wrote: »

Thanks for the reply.

At the time, it was a gamble to try and nail two birds with one stone, I'm feeling the pinch now as it does require a bit of water waste/flow before the hot begins to come through.

So are you suggesting that its the heat of the expanded water I'm feeling on the outlet pipe? and not the tank itself trying to heat all the water in the tank as well as the water going to the tap?

If this is the case, ill live with it for a while, but I think ultimately Ill end up moving to a tank per sink.

If I understand Gary's suggestion correctly, you will have a mugfull or so of warm water coming out if you cold tap when first turned on. There is little to be done about that unless you change to single taps.
As said above; good insulation. I think your losses would then be minimal.

You could check it by turning EVERYTHING off and reading your meter then and an hour later. Of course not using any of the taps during that time.

At times when you have two different water standing pressures with some mixing taps which are turned off the water can flow across the two sides of the mixing tap as it try's to equalise the pressure, this allows the hot water to creep out of the heater, up the draw off and across the tap leaving the tap heated.

Encrypted Pigeon

I follow what you are saying now. My mind is pretty much made up now that I will look to a different arrangement. Thanks for the input.