heatrae sadia 25l 9004010.

[Matt0029]

Has anyone one fit or serviced one of these before; Heatrae Sadia 25l 9004010.
It a 25 litre hot water storage cylinder.

 

[Matt0029]

Thanks so it can be mains in and still classed as gravity out?

 

[ShaunCorbs]

Thanks so it can be mains in and still classed as gravity out?

Could be might be worth phoning heat rae

 

[Matt0029]

Thanks I'll give a ring. I have the manual there is a filter on the cold main in it. There a low and high water level sensor that opens and closes the solenoid. Which must be working as opened to fill it and shut off when full. And said took a long time to fill the 25 litre tank.

 

[John.g]

I came across a ~ 20L heater with no expansion vessel that had one of these pressure relief valves set to I think 6 bar but it also had a anothenon return valve valve inside the PRV to enable filling and also stopped the cylinder emptying in the event of mains water failure, it didn't have any solenoid valves and allowed the expansion to take place back through the mains with a minimumm distance specified to avoid hw water issuing from a cold tap if too close, don't know how your cylinder operates, its hardly a gravity unit if it requires pressure to push the water out of it?

Ariston 571730 PRV installed on the cold inlet at the cylinder.

 

[Matt0029]

It has a high and low water pressure sensor on the unit linked to the solenoid valve

 

[Matt0029]

When I turn the hot tap on the solenoid is in the closed position. As this operates then the low water level sensor opens it again. So if opening the hot tap and the solenoid is closed. It would be gravity?

 

[Matt0029]

First time I've come across one like this before there expensive units

 

[John.g]

If it gravity then there has to be a air vent in the cylinder to allow the level to drop to fall enough to open the solenoid valve? maybe it contains a air bubble like the megaflo and the like?
Are there HW draw offs above the cylinder or on the same level?

 

[Matt0029]

It has a breather pipe coming out of the top. With no valve on it.

 

[John.g]

Is it a vacuum breaker?, if so, then any HW draw off has to lower than (at least) the level of of the low probe.

 

[Matt0029]

Thanks yes the draw off are all lower the the unit. Breather pipe has tundish on it.

 

[John.g]

Maybe worth checking that for scale build up, if its restricted then the flow from any hot tap will be restricted as well except its just a pure vent pipe,, any photo or description of the unit?.

 

[Ben-gee]

Check the breather pipe for blockage, kink, hernia.
If air can’t get into the unit - water can’t get out.

 

[Matt0029]

Check the breather pipe for blockage, kink, hernia.
If air can’t get into the unit - water can’t get out.

Thanks I think there is a filter in the breather pipe. But there isn't much distance between the bottom of the unit and the hot taps. Only 1meter tops. So 0.1bar.

 

[John.g]

I have a upstairs "1/2" cartridge tap gravity fed from ~ 0.25M that flows 4.0LPM, so if the water level in your cylinder is, say 0.15M above the tap then you might expect ~ 3.0/3.1LPM.

 

[Matt0029]

The distance between the base of the cylinder and the hot tap outlet is around 1meter. So this would give 0.1 bar pressure. What flow rate would this likely give?

 

[John.g]

Maybe 2.0 to 2.5 LPM based on my tap.qqqqqqqqqq 50 chacters to post

 

[Matt0029]

Thanks I don't think it is that at the moment. Possibly abit of an airlock/ breather pipe blockage.

 

[Matt0029]

If it does flow at a decent enough level. If were to fit dual flow taps. Doesn't mix in tap mixes after leaves the spout. Would single checks not be needed to avoid back flow

 

[John.g]

Probably not, I have a d/stairs mixer like that where it mixes in the spout, 3.0bar cold & 0.5bar Hot gravity, no problems.