Slow hot water supply

[lemuzz]

Hi The hot water supply to my kitchen sink is very slow. This is due to a long pipe run about 15 to 20 metres from the low pressure cylinder. Cold supply is very good, as is the hot supply to bathrooms, showers and laundry which are much closer to the cylinder. I wonder if an in line boost pump would be of any help. The house is 15 years old with good plumbing.

 

[pekasus]

The 15 meter run wouldn't have anything to do with pressure unless it is a vertical run. My guess is that there is a valve somewhere along the line that is partially closed. Or, if you have galvanized steel pipes, it may be corroded.

Make sure the valves along the line to the kitchen are open all the way and functioning.

 

[lemuzz]

The 15 meter run wouldn't have anything to do with pressure unless it is a vertical run. My guess is that there is a valve somewhere along the line that is partially closed. Or, if you have galvanized steel pipes, it may be corroded.

Make sure the valves along the line to the kitchen are open all the way and functioning.

Hi Pekasus. The only valve in the system from the cylinder would be a tempering valve but this is only on the bathroom runs and not the kitchen run. Would friction in the plastic pipe and bends not be a cause of slow hot water in the kitchen line? If not I wonder if it would be the kitchen sink mixer? If it could be the mixer, it may be a similar price to install a boost pump at $200 to give give good pressure to all hot taps as opposed to a new mixer at $160 Regards.

 

[pekasus]

Before you spend the money on a pump, check the material. If it is galvanized steel, one sign of corrosion are little 'rust warts' on the outside of the pipe. If the supply lines are in good shape, then the loss over 15 meters shouldn't be the cause.

Just to make sure, is the kitchen at the same elevation as the bathroom? If there is more vertical rise to the kitchen, then that could explain it and you would need to boost the pressure.

If you can isolate the problem to the mixer, it would be better to replace that. If you have good pressure to the other fixtures, boosting the pressure could cause new problems. To test the mixer, make sure to shut off the faucet supply, remove the hose, and test the pressure when it is not going through the faucet. If it is good, then its the faucet.

 

[lemuzz]

Before you spend the money on a pump, check the material. If it is galvanized steel, one sign of corrosion are little 'rust warts' on the outside of the pipe. If the supply lines are in good shape, then the loss over 15 meters shouldn't be the cause.

Just to make sure, is the kitchen at the same elevation as the bathroom? If there is more vertical rise to the kitchen, then that could explain it and you would need to boost the pressure.

If you can isolate the problem to the mixer, it would be better to replace that. If you have good pressure to the other fixtures, boosting the pressure could cause new problems. To test the mixer, make sure to shut off the faucet supply, remove the hose, and test the pressure when it is not going through the faucet. If it is good, then its the faucet.

Hi. The pipe is poly butyl 12mm about 12 years old and the bathrooms both have good hot supply from standard non mixer taps although the showers both have, with hot supply coming from a low pressure cylinder and a run of about 6 metres to one and about 8 metres to the other. When using either shower only a slight drop in temperature is felt when any other tap is opened. There is a tempering valve fitted to the shower line.
At the other end of the house,( about 15 metres away and which is single story and on one level ) at the kitchen sink with a sink mixing tap (which I believe is a low pressure mixer) the hot flow is very slow. All runs are reasonably straight. I agree with you that as the kitchen run is only about 8 metres further, flow and pressure should not be seriously different, but it is. If I measure and time the flow from the hot taps, and also through the sink mixer, would that help to identify the problem?
Perhaps I should remove the mixer and then check the flow. Regards Lem.

 

[lemuzz]

Hi. The pipe is poly butyl 12mm about 12 years old and the bathrooms both have good hot supply from standard non mixer taps although the showers both have, with hot supply coming from a low pressure cylinder and a run of about 6 metres to one and about 8 metres to the other. When using either shower only a slight drop in temperature is felt when any other tap is opened. There is a tempering valve fitted to the shower line.
At the other end of the house,( about 15 metres away and which is single story and on one level ) at the kitchen sink with a sink mixing tap (which I believe is a low pressure mixer) the hot flow is very slow. All runs are reasonably straight. I agree with you that as the kitchen run is only about 8 metres further, flow and pressure should not be seriously different, but it is. If I measure and time the flow from the hot taps, and also through the sink mixer, would that help to identify the problem?
Perhaps I should remove the mixer and then check the flow. Regards Lem.

I have just measured the flow. The bathroom has a flow of 12 litres per min and the and the sink mixer, a flow of 5.5 litres per min. ( Hot water flow through the taps and mixer )

 

[speedbump]

I agree, don't buy a pump. You will be opening a new can of worms. Especially with a $200.00 one.

 

[pekasus]

I have just measured the flow. The bathroom has a flow of 12 litres per min and the and the sink mixer, a flow of 5.5 litres per min. ( Hot water flow through the taps and mixer )

I assume that you measured the flow through the faucet. I would shut off the water at the sink, disconnect the faucet, and test the flow there. This will isolate the the line from the mixer. If you still notice the low pressure, there must be some obstruction in the line, like a valve that is not open all the way or is not functioning properly.

 

[havasu]

I assume that you measured the flow through the faucet. I would shut off the water at the sink, disconnect the faucet, and test the flow there. This will isolate the the line from the mixer. If you still notice the low pressure, there must be some obstruction in the line, like a valve that is not open all the way or is not functioning properly.

^ This is sound advice!

 

[lemuzz]

I assume that you measured the flow through the faucet. I would shut off the water at the sink, disconnect the faucet, and test the flow there. This will isolate the the line from the mixer. If you still notice the low pressure, there must be some obstruction in the line, like a valve that is not open all the way or is not functioning properly.

Thanks Guys, This is my next step but a heavy snow dump has put a hold to this in the meantime. When things sort themselves out weather wise I will do this and let you know the result.