hot water problems

[Connor Williams]

Hello guys happy christmas one and all.
Am having a problem with an S plan heating system in a large property and wondered if anyone had any tips or ideas as to what the problem can be.

Basically when the customer has the hot water and heating on constant the hot water is fine. But when they set the water & heating to fire up in the morning at 5.40am, the heating is fine but the water is just lukewarm after a couple of hours.

They have a big old floor standing boiler with a hot water cylinder.
I have checked the zone valves, cylinder stat and all seem to be working correctly, this problem only occurs when the hot water & heating are on the timer.

It's a Honeywell programmer, my only thought is that for some reason the system is heating the rads first and not getting the hot water up to temperature quick enough when on the timer.
Any feedback or advice would be greatly appreciated, many thanks.

All the best Connor.

 

[SimonG]

Shared pump or pump for heating and pump for hot water? If two are they both set at the same speed?

 

[Connor Williams]

Shared pump or pump for heating and pump for hot water? If two are they both set at the same speed?

Hello, yes it's a shared pump and a big property with three levels, actually I didn't check the pump speed.
the hot water cylinder is right next to the boiler on the ground level and the pump is between them, literally 2ft away from the cylinder.
when on constant the PIPEWORK either side of the zone valve for the hot water gets hot enough, the cylinder stat seems to work okay and looks fairly new.

 

[Crinkmeister]

When you say hot water and heating on constant, do you mean with both the switches on the controller set to ON? Have you seen this behaviour yourself? I'm thinking controller fault. When on timer, does the HW zone valve open?

 

[GasmanxxxR1]

bit early for christmas greetings isnt it?

 

[Crinkmeister]

I thought so and tried to ignore it, but you've just reminded me!

 

[Connor Williams]

When you say hot water and heating on constant, do you mean with both the switches on the controller set to ON? Have you seen this behaviour yourself? I'm thinking controller fault. When on timer, does the HW zone valve open?

Hello yes I turned up the cylinder stat which opened up the valve and fired the boiler , when we left the water on constant and not on the timer the water was lovely. I could set the timer to come on and see if it does open up the zone valve and fire the boiler properly.
And yes , too early for Christmas greetings apologies, I'd had a drink.
i am thinking you may be right with the timer/controller fault

 

[zzzjim]

Maybe not with Mince pies in supermarkets ( My guts are convinced its Xmas already )

Can a blast of "Just" hot water be done in middle of night ( when all a sleep ) Have not looked up timer

 

[lame plumber]

if they are on constantly and it warms it would indicate that the flow to cyl is to small and heating is nicking all the heat till house is warm and s plan closes ch side allowing hw to heat up, so flow to cyl being limited by balancing valve being shut to much or auto bypass opened too much etc etc

 

[mountainman]

I had a similar problem once, the hot water coil turned out to be sludged.

 

[Connor Williams]

I had a similar problem once, the hot water coil turned out to be sludged.

Thanks for the tips guys, there was a gatevalve on the flow to the cylinder after the hot water zone valve and before the pipe joined the cylinder and that was fully open.

There was a 15mm bypass pipe with a gatevalve but I didnt really want to turn this down as the heating system is huge (three level property)

In the end I programmed the hot water to fire up thirty minutes before the heating at 5am and this seems to have cured the problem by giving the hot water a head start.

So, with the programmer timed to fire up heating & hot water togethar in the morning, the heating circuit was stealing all the heat it seems. I'll see how they get on thanks again