Building Heating Controls

[Jobos]

Has anyone got experience of building heating controls? The reason I ask is because it's like a oven in the school and the site team are having problems controling the heating so I thought I would throw this out there.

 

Looking at the image the system is calling for heat but the internal temperature has already exceeded the set point. Can anyone see what the problem is?

 

[Andrew_C]

Afraid you need a proper man*... We had similar last week or two. Eventually maintenance got the right person in who found the burned out circuit board.

 

*or woman

[Jawloms]

Is it because the other set point top right hasn't been hit for some reason? I assume they are "OR"? Looks like you have a heat exchanger in there. Wish we had one. Caused all sorts of problems without it!

[Jobos]

Is it because the other set point top right hasn't been hit for some reason? I assume they are "OR"? Looks like you have a heat exchanger in there. Wish we had one. Caused all sorts of problems without it!

 

Not sure about flow temp but both space temp setpoints have been reached so heating should go off. I don't normally have anything to do with these controls so bit lost as to what should it be set to but playing with OAT hold off setting and changing that to on the boilers go off. Not clear at all!

 

@Andrew_C I've already said they need to get the controls serviced which I understand is different to having the boilers serviced but my advice falls on deaf ears. The gas saving would pay for this many times over.

[TheRobins]

As suggested, needs some diagnostics doing, looks ok from the picture.

 

Can you delete any time schedules, or put it into "summer" as a temporary fix (Unless they also supply hot water, and you do not have a sepearte hot water boiler)

 

I am actually on hold to Viessman at the moment trying to sort out a warranty claim on a new boiler.

[Chris_Cook]

Have you tried turning it off and on again?

 

More seriously, there is a 'reset' button and a 'heating times' button on your screenshot. I'd try those and see if that makes a difference, or if you can change the times for the summer.

 

They should also have left a building systems manual behind when this was installed.

[Aprice]

I'd suggest power cycling the control panel just in case. Don't suppose there's a document floating around with the control strategy on it, which should at least explain what the system is supposed to do.

[JOrdan01070]

Not sure but you have OAT (Outside Air Temp)set to 16 but it looks to be reading 14 so the system will call for heating until the OAT is at or higher than 16.

[steveg]

Do you have anything else that calls for heat? Our heating can be off, but the air handling unit in our kitchen is linked into a heating loop and that system can call for heat. Because of the bad way it is designed, this can then cause heating to distribute round the school (we have to manually shut off valves to stop it happening)

[Andrew_C]

OAT - Outside Air Temp It won't be trying to bring that up...

[Jobos]

I think the OAT is set incorrectly as switching this to on has shut the boilers off. I’ve googled OAT hold off but there isn’t much info on it.

[Chris_Cook]

I think the OAT is set incorrectly as switching this to on has shut the boilers off. I’ve googled OAT hold off but there isn’t much info on it.

 

There should be a temp sensor outside the building for the OAT. I'd check if that's reading accurately - it might be out of calibration. I'm not sure where you are based, but its warmer than 14 degrees here.

 

The "OAT Hold off" button will probably override that.

 

You might need to check that you still get hot water at the taps if the boilers do both.

[PotNoodleTech]

If the system is meeting the space temp set point at 16 which it is - it should stop calling for heat. Like Jowloms said the actual water temp set point isn't being reached and the water temp set point is usually calculated by taking into account outside temperature and the indoor space temp set point and combining it with a a low and high temperature setting e.g. at 20 degrees c water temp = 20 and at 0 degrees c water temp = 80 degrees c

 

If those two up and lower settings are totally wrong (e.g. at 20 degrees c setpoint set water temp at 70 degrees c) that would cause the heat to stay on trying to get the flow return water temp to 70c all the time?

 

heating systems, like catering systems, are absolutely garbage I've never seen one that works well or is easy to use.

[Jobos]

Thanks everyone.

 

With the OAT hold set to off it seems better today but like others have said it needs looking at and adjusting. I was speaking with a site manager at another school and he said they have the controls serviced not just the boilers and pumps. This school enquired about the control service but thought better of it when they seen the cost. It's just cost cutting but the school will pay more in the long run.

[Chris_Cook]

If its a networked system, then this is one to keep on top of especially with regards to cyber security.