Navitron Renewable Energy and Sustainability Forum

Green Building and Design => Rainwater Harvesting / Grey Water Recovery & Processing => Topic started by: Pilgrim on July 26, 2017, 11:00:26 AM



Title: UFH actuators to control water storage system?
Post by: Pilgrim on July 26, 2017, 11:00:26 AM
I have a large tank in my loft. I'd like it to automatically drain if it gets too hot. I was wondering about using an UFH actuator to control the drainage. If the temperature was too hot, it would open and drain. Any views?


Title: Re: UFH actuators to control water storage system?
Post by: Sean on July 26, 2017, 11:29:37 AM
Seems a shame to waste all of that energy.

I cant see the advantage of using an actuator, what's wrong with using a 2 port motorized valve and a pipe stat ?





Title: Re: UFH actuators to control water storage system?
Post by: Countrypaul on July 26, 2017, 11:50:03 AM
What is the tank used for and why do you feel you need to drain it when it gets too hot (and what is too hot)? It does sound like it will be a complete waste of energy at the least, but possibly more especially if it is mains water. Is the tank insulated properly?


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 26, 2017, 11:55:02 AM
As it's in the loft, I'll insulate it, but there needs to be a failsafe to prevent legionella if it gets above 20


Title: Re: UFH actuators to control water storage system?
Post by: Sean on July 26, 2017, 12:14:40 PM
Have you ever measured the temp as being anywhere close to 20 ?


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 26, 2017, 12:53:05 PM
The current space, before being isolated from the rest of the building regularly hovers around 19 20 degrees.


Title: Re: UFH actuators to control water storage system?
Post by: TT on July 26, 2017, 01:00:47 PM
Just make sure the tank is the right size for the premises.
Good turnover of cold and hot water and you will be fine.

No point in doing all that work if you aren't going to measure temps at sentinel taps, remove dead legs, c&d tanks, shower heads etc


Title: Re: UFH actuators to control water storage system?
Post by: Sean on July 26, 2017, 01:19:55 PM
The current space, before being isolated from the rest of the building regularly hovers around 19 20 degrees.

I'm guessing that'll be ambient air temperature ?

If it's a large tank, and given a reasonable amount of turnover (use) it'll take a much higher ambient temp, and a fairly lengthy period of time for the tank contents to get to ambient.


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 26, 2017, 02:39:45 PM
Seems a shame to waste all of that energy.

I cant see the advantage of using an actuator, what's wrong with using a 2 port motorized valve and a pipe stat ?





Ah, so a 2 port motorized valve draws less electricity. I thought an actuator would be cheaper.


Title: Re: UFH actuators to control water storage system?
Post by: bxman on July 26, 2017, 02:50:47 PM
This is rainwater for flushing loo and for  the washing machine. ?

I would just record the temp.

It would IMO be very unlikely to get that warm in this country.

If you were worried take the inflow to the bottom of the tank and any overflow would naturally discharge the warmer water from the top of the tank .


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 26, 2017, 03:02:32 PM
This is rainwater for flushing loo and for  the washing machine. ?

I would just record the temp.

It would IMO be very unlikely to get that warm in this country.

If you were worried take the inflow to the bottom of the tank and any overflow would naturally discharge the warmer water from the top of the tank .

My initial plan was to just record the temperature, but I thought that might not be sufficient for the authorities.

Great idea about taking the fresh water to the bottom BTW!


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 27, 2017, 07:16:22 AM
Does anybody know a simple way to control a motorised valve to drain if the water reaches 20? Ideally I would like to control this with another valve that fills the tank from the mains if the level is too low, but not if the water is being emptied.


Title: Re: UFH actuators to control water storage system?
Post by: Countrypaul on July 27, 2017, 08:42:15 AM
You could use one valve to open at 20C and drain the tank, whilst having another that stops the filling at say 15C.

Filling to the bottom of the tank from mains water needs to be setup so that water cannot be sucked back into the mains pipe which normally means an air gap using a ball valve (check the regs).


Title: Re: UFH actuators to control water storage system?
Post by: Antman on July 27, 2017, 09:08:33 AM
Probably worth pointing out that motorised valves intended for heating systems are not designed to be used as flow control on open systems i.e. they should not be used as a tap (shut-off valve). They are designed for closed-loop systems where there is a balanced static pressure on both sides.
To put another way, they are likely to 'let-by' if you try to hold back a head of water to open drain.

I would have thought good insulation around the tank will keep it below 20 especially if the water is being used. We don't worry about mains filled tanks getting too hot do we? And the incoming water fill temp is probably similar over summer.
Regards
Antman


Title: Re: UFH actuators to control water storage system?
Post by: TT on July 27, 2017, 01:55:55 PM
Not that I agree about this scope of works being necessary, but what about a solenoid valve as used in washing machines etc.



Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 28, 2017, 06:57:46 AM
Probably worth pointing out that motorised valves intended for heating systems are not designed to be used as flow control on open systems i.e. they should not be used as a tap (shut-off valve). They are designed for closed-loop systems where there is a balanced static pressure on both sides.
To put another way, they are likely to 'let-by' if you try to hold back a head of water to open drain.

I would have thought good insulation around the tank will keep it below 20 especially if the water is being used. We don't worry about mains filled tanks getting too hot do we? And the incoming water fill temp is probably similar over summer.
Regards
Antman
Thanks Antman. So the drain would probably be okay for draining a static tank, but not controlling the mains input?


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 28, 2017, 07:16:12 AM
Something like this? http://www.solenoid-valve.world/by-industry/water-industry/nylon-water-solenoid-valve


Title: Re: UFH actuators to control water storage system?
Post by: Antman on July 28, 2017, 08:41:03 AM
Thanks Antman. So the drain would probably be okay for draining a static tank, but not controlling the mains input?
Hi Pilgrim
No because the valve still has a differential static pressure owing to the 'head' on the tank one side and atmospheric pressure on the outlet.
Antman


Title: Re: UFH actuators to control water storage system?
Post by: Pilgrim on July 28, 2017, 08:58:55 AM
Thanks Antman. So the drain would probably be okay for draining a static tank, but not controlling the mains input?
Hi Pilgrim
No because the valve still has a differential static pressure owing to the 'head' on the tank one side and atmospheric pressure on the outlet.
Antman


Thanks! So solenoids for both then?