Hi my hive system is not shutting down the hot water correctly. I have changed the cylinder thermostat and at 0 on the tank thermostat when turned and call for hot water is on hive, as you turn it it does cone on to heat and if turned down to 0 turns off as well. If it's set to say 60 with just the hot water only it gets really hot. I have had boiler lock outs with the baxi solo boiler as well. Heating turns on and does what it's supposed to do. It does if asked by hive turn on the hot water and turn it off. I suppose it must be a wiring fault.It's a 3 wire thermostat with brown on 1 blue on 2 and black on common. Many thanks.
Hive overheating hot water.
- Thread starter Simp655
- Start date
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wiring colours mean absolutely nothing in a heating system, pics are best of everything
Did it work correctly before the Hive was installed? If not, did anything else happen just before the 'fault' appeared?
If it previously worked OK and nothing changed, it won't be a wiring fault, wired don't move themselves.
If it previously worked OK and nothing changed, it won't be a wiring fault, wired don't move themselves.
Yep it did on the original timer. Hive was installed it also worked fine. I started having boiler lock outs on the baxi then during covid I called a local heating firm. To be honest they weren't much good they sent a bloke he cut one of the wires to the HW 2 port valve of the tank side then they had to send in another bloke eventually he changed the electronic head but not the valve,why he didn't do the lot I don't know. Maybe they screwed the wiring up
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Sounds quite likely a wiring fault then. If you need any more help as per @ianmcd a photo would be good and the make and model of the cylinder thermostat if not obvious.
I asked the question because your title blames the Hive for the overheating, but obviously it's not the Hive if it was already doing it before the Hive was installed.
One thing that's curious is that systems with a 3-Port valve use all three cylinder thermostat terminals. Your system which you describe as having 2-Port valves uses only two.
Changing just the powerhead is a very common repair. They are specifically designed to be like that because it saves having to drain down the heating system and saves a lot of time. Also handy for a DIY fix on a Sunday afternoon.
This is only a guess, but it might be possible, that to stop the boiler overheating, the valve was fixed permanently open so that there was always a route for the water to flow through, the wiring probably would have to be altered to achieve this (otherwise the hot water only comes on with the CH). If the HW valve were fixed permanently open the water will get hotter and hotter whenever the boiler is running. If that is the case, it should have been explained as a temporary fix. Although, it should have been rectified when the new powerhead was installed.
I asked the question because your title blames the Hive for the overheating, but obviously it's not the Hive if it was already doing it before the Hive was installed.
One thing that's curious is that systems with a 3-Port valve use all three cylinder thermostat terminals. Your system which you describe as having 2-Port valves uses only two.
Changing just the powerhead is a very common repair. They are specifically designed to be like that because it saves having to drain down the heating system and saves a lot of time. Also handy for a DIY fix on a Sunday afternoon.
This is only a guess, but it might be possible, that to stop the boiler overheating, the valve was fixed permanently open so that there was always a route for the water to flow through, the wiring probably would have to be altered to achieve this (otherwise the hot water only comes on with the CH). If the HW valve were fixed permanently open the water will get hotter and hotter whenever the boiler is running. If that is the case, it should have been explained as a temporary fix. Although, it should have been rectified when the new powerhead was installed.
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Thanks mate. Yep into the cylinder it's a 2 port valve on the pipework on the way into the cylinder. I know hive has hw on and off on the control unit being 2 zones. The boiler has sometimes sounded like no water flow so I'm thinking the 2 port valve is sticking hence no water flow on fire up and thus lockout from the boiler As they were so kind to not fit the valve like I had told them to do the next step is to get that fitted and see if that changes anything. I also have pump running on which I presume is down to the head getting stuck but it doesn't happen all the time. I'm not sure how to drain down to fit the valve so I might have to get someone to do it and check all the port head wiring to make sure they didn't muck it up
It only does it if the boiler locks out and I have to reset it. The wiring centre us an late 80s birds nest of wires. I might have to isolate the main supply take the cover off and actually trace how that guy has wired in the HW head and the cylinder thermostat wiring along with the wiring to the hive control. There are 3 wires on the cylinder stat plus earth. Im not sure how it should have been wired to the control unit in order to have a call for heat, satisfied and common wiring and as for the head I'm not sure. I know if the stat is on 0 and hive calls for HW the green light stays lit but the pump and boiler and head remain off until the stat is tripped past the on point on the stat at around 30c.
Are you sure the immersion hasn't been left on?
Does the boiler and pump switch off if you turn the cyl stat down with the boiler running?
Does the boiler and pump switch off if you turn the cyl stat down with the boiler running?
Did a test on it this evening. Set hive to turn on HW set cylinder stat to 50c it carried on heating the hot water until I nudged it down a bit. Then the HW valve actuated shut the water off but it did not tell the boiler to shut down hence the boiler started kettling and I turned it off on the power quick. It looks like the new stat is working but it's not shutting down the boiler as it turns off the 2 port valve.
You have to understand system operation
Timer opens appropriate valve if the associated thermostat is calling.
Valve opens. When fully opened, auxiliary switch in the valve fires the boiler.
From your post it is evident that cylinder thermostat is not being satisfied hence 50 degrees is not being reached- should be 55. This should be looked at as to why target temperature not achieved.
When the valve is closed, boiler is still on line.
Not going to hold your hand here, if you cannot work it out, you should get a pro in to sort the issue
Inside the motorised valve is a small microswitch, when the valve winds to the open position it presses the switch. This switch then starts the boiler. When the valve closes the switch is released and the boiler goes off.......or that's what should happen if it's wired up correctly.
The switches are known to stick in the on position and not release when the valve closes, if that happens the boiler would keep running.
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Yep I'm going to get someone to look at it. When the hot water only is on on hive when turning off on the button in kettle the boiler by cutting the water supply to it by not turning off the boiler. It's wiring those fools who looked at it have mucked it up.
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