Hot Water, no pressure after rainwater ran out

[timgrigg]

Hi, I have a Rheem solar hot water system (split so the tank is on the ground), boosted by mains, we are on rainwater, so have an electric pump to supply water to the house. We ran out of rain water the other day and got a mains water delivery, (only the 5th time this summer!) since then we have had very little hot water pressure, the cold water is fine, I'm thinking there is air in the system and can hear gurgle noises when the hot water is on, but, no idea on what to do, can you bleed hot water tanks?, any ideas would be appreciated.<o></o>

By the way, I have cleaned a small filter in the tank inlet, this sometimes gets clogged up when water from the bottom of the rainwater tank passes though it, so it's not the filter.<o></o>

[Barry_White]

Tim

Is that the model that circulates the water through the solar panels with a small pump.

If so you may be able to bleed any air from the tank at the solar panels by undoing one of the plugs on the end of the solar the higher up the better.

I thought there was a blled valve near the outlet for the hot water.

I would have thought that if you were on mains pressure the air would eventually be expelled through the taps. You may have to run it for a while.

[bricks]

Although an obvious waste of water I suggest finding the furthest point away from you outlet of the solar heater ( If it's central then both ends is ok to). Turn these taps on for five to ten minutes and see if the pressure getts better. A higher point is better.

[mugwoody]

Agreed with others on this.

Air lock (a big volume of air caught up in the pipework which cannot be expelled) is the most logical problem.

IMHO the following procedure should be followed

First turn off the pump.
Next, open a valve or plug at the highest (vertical) point in the system.
Turn on the pump and watch the water flow from the open point in the system.
Once the flow is smooth and free of air you can replace the plug or close the valve while the pump is running.
Open the downstream valves and bleed the air from the rest of the system.

The problem is that air is compressible while water is non compressible hence, while the pump is running there will be compression of the entrapped air and this will be fluid enough to displace the water from the pump when turned off.

Trust this is understandable.

Peter