Increased Water Pressure Issue

[MichaelB]

I am having increased water pressure issues and can not figure out why. I had a tiny hole develop in the expansion tank of my hot water heater and had the tank replaced. Ever since them, it seems like the water pressure is more forceful than what it was prior to the replacement, especially when flushing the toilets (it seems like it is a harder cutoff). I can run the hot water out of the tap from one of the faucets for 30-45 seconds, then flush a toilet and everything seems normal. However, a few minutes later it seems like the increased water pressure is back. I have checked the incoming water pressure and it does not appear that it has changed. Any ideas what could be going on and how it can be fixed?

 

[SimonG]

Sounds like it's back to normal after having the expansion vessel repaired or a failure of a pressure reducing valve.

 

[Stigster]

Sounds like it could be a blocked inlet strainer on your hot water tank. Do you have what is known as a balanced cold supply where the cold distribution to the rest of the house is taken from the cylinder control group?

I say this because the main symptom of a partially blocked inlet strainer is the system performing as you describe - A burst of what looks like high flow/pressure from the outlets which then dies back to a much lower flow.

Because the inlet is partially blocked, when the taps and other outlets are closed, the water is able to fill the tank and the pressure increases within until it equalises with the incoming mains pressure, this also happens in your expansion vessel, compressing the air inside. Then you open an outlet and the now fully pressurised system give "full performance" for a short while whilst the expansion vessel "relaxes" and pushes the water through (acting like a small accumulator). At this stage the flow then tails off to whatever amount is able to pass through the restricted inlet strainer.

I hope this makes some sense the way I've tried to explain it.

 

[MichaelB]

Sounds like it could be a blocked inlet strainer on your hot water tank. Do you have what is known as a balanced cold supply where the cold distribution to the rest of the house is taken from the cylinder control group?

I say this because the main symptom of a partially blocked inlet strainer is the system performing as you describe - A burst of what looks like high flow/pressure from the outlets which then dies back to a much lower flow.

Because the inlet is partially blocked, when the taps and other outlets are closed, the water is able to fill the tank and the pressure increases within until it equalises with the incoming mains pressure, this also happens in your expansion vessel, compressing the air inside. Then you open an outlet and the now fully pressurised system give "full performance" for a short while whilst the expansion vessel "relaxes" and pushes the water through (acting like a small accumulator). At this stage the flow then tails off to whatever amount is able to pass through the restricted inlet strainer.

I hope this makes some sense the way I've tried to explain it.

This makes sense. How would I go about checking this and/or correcting the problem?

 

[Stigster]

In the UK it requires a qualified person to work on as it is an unvented hot water system. However your regulations may be different. The strainer is found as part of the pressure reducing cartridge assembly in the group inlet to the cylinder. Can you post a picture of your cylinder setup so we can see what you are dealing with?