Mains Pressure Hot water System - Brown Sludge

[Chuck]

It's slimy, no dead legs, everything brand new. We have secondary return pump, runs 24 hours.

A circulation loop needs to be well-insulated, or it will dissipate a lot of heat, and the section I can see has no insulation. . . Most domestic installations have the secondary return pump on a programmer so it only runs at times when hot water is being used by the household.

What is the temperature of the water in the tank? Is it's heater on all the time?

 

[Michaelwgroves]

A circulation loop needs to be well-insulated, or it will dissipate a lot of heat, and the section I can see has no insulation. . . Most domestic installations have the secondary return pump on a programmer so it only runs at times when hot water is being used by the household.

What is the temperature of the water in the tank? Is it's heater on all the time?

Other than in the boiler cupboard, all pipes are lagged. This is a large HMO, the occupants don’t have a regime, so shower throughout the day. So need to have hot water snd pump on 24/7.
The water temp is set to 55.

 

[Michael Groves]

A circulation loop needs to be well-insulated, or it will dissipate a lot of heat, and the section I can see has no insulation. . . Most domestic installations have the secondary return pump on a programmer so it only runs at times when hot water is being used by the household.

What is the temperature of the water in the tank? Is it's heater on all the time?

Other than in the boiler cupboard, all pipes are lagged. This is a large HMO, the occupants don’t have a regime, so shower throughout the day. So need to have hot water snd pump on 24/7.
The water temp is set to 55.

If in doubt, get a sample analysed by a lab that offers water quality tests. Expect to pay £50-£100 for a one-off test but it should give a definitive result. Call them and ask their advice about what type of test you need before placing an order.

What would you google for this, have you ever used such a company?

 

[exedon2]

I take it the hot water system and secondary return is all copper no plastic?

 

[Chuck]

Other than in the boiler cupboard, all pipes are lagged. This is a large HMO, the occupants don’t have a regime, so shower throughout the day. So need to have hot water snd pump on 24/7.
The water temp is set to 55.

What would you google for this, have you ever used such a companyrown

If you Google "uk water analysis lab test" you'll find many firms that offer tests of various types. If you include your county or town you'll probably find half a dozen within easy reach. The big national firms have nice websites with lots of useful information. I use a small local lab who are a bit cheaper and v. helpful with advice. The main gotcha is you can pay £50 for a test but if it's not the right test for your circumstances it won't tell you anything useful.

The landlord needs to do a legionella risk assessment and IMO identifying the nature of the brown sludge to confirm it's not a health hazard should be part of that. 55°C, for example is below the HSE recommendation for stored water, which is 60°C so that's something that might need to be considered.

 

[Michael Groves]

I take it the hot water system and secondary return is all copper no plastic?

There is a mix of Copper and Hep2o

 

[Michael Groves]

If you Google "uk water analysis lab test" you'll find many firms that offer tests of various types. If you include your county or town you'll probably find half a dozen within easy reach. The big national firms have nice websites with lots of useful information. I use a small local lab who are a bit cheaper and v. helpful with advice. The main gotcha is you can pay £50 for a test but if it's not the right test for your circumstances it won't tell you anything useful.

The landlord needs to do a legionella risk assessment and IMO identifying the nature of the brown sludge to confirm it's not a health hazard should be part of that. 55°C, for example is below the HSE recommendation for stored water, which is 60°C so that's something that might need to be considered.

It was originally 60, but we turned down to prevent risk of scolding. But we then installed Thermostatic Mixing Valves on the taps closest to boiler. But then never turned back up. I've just checked and it was actually 57, we've now turned back up to 60 and will keep it at this.
Thanks for water test idea.

 

[exedon2]

Should be no plastic at all in a secondary return
Afraid to say needs changing against manufacturer instructions
Wonder if that's cause of problem?

 

[Michael Groves]

Should be no plastic at all in a secondary return
Afraid to say needs changing against manufacturer instructions
Wonder if that's cause of problem?

I spoke to Hepworth at long length about this before install. They advised they have not tested on secondary return, so can't advise to use Hep2o. Therefore, their advise has to be don't use.
So in theory, there is no reason not to use.
But, I agree the plastic pipe is a contender, but why?

 

[exedon2]

There is a previous thread on secondary returns in plastic have a look at that .It seems wavin don't recommend it now.