Week showers due to dead pump?

[mattltm]

Hi all,

I have a small B&B with 8 rooms and have started to get complaints about the showers. I'm going to get someone in to do any work needed but wanted to work out what's going on.

I have a vented HW system that is fed from a tank in the loft of a 3 story building and a pump that circulates the HW around the building. Complaints started about 2 months ago and are usually about the showers on the top floor. I also noticed that about a month ago the pump started to make intermittent noise. Sounded like an engine revving or a light airplane flying over. If I turned the pump off and then back on again then the noise would stop most times.

To check if the pump was working I done the following:

With the boiler on but the pump off, I felt the hot water pipe (part of the loop, not a take off to a tap) on the top floor. It was cold.

I turned the pump on, waited 1 minute and felt the same pipe again. It was warm. There had been no outlets open so I guess that the pump is pushing the hot water around the loop ok.

Next, I took the showerhead off of one of the showers that I receive the most complaints about. I filled up a 2L bottle, 3 times and times each run.

The average fill time with the pump on was 30 seconds.

The average fill time with the pump off was also 30 seconds.

I was expecting there to be more flow with the pump on. I guess my question is:

Should the hot water circulating pump increase the flow rate when it is turned on?

Thanks,

Matt

 

[danplumb]

No not neccesserily it is just a circulating pump, it just ticks over to slowly circulate the water around the system to stop long deadlegs of pipe full of cold water, it circulates the hot water around the pipes so you get instant hot water when a tap is opened, you need a shower pump to get a good pressure for a shower.