Hot water issues

Fernagx

We have an S-Plan unvented central heating/water system with a hot water cylinder. The boiler is set to come on twice daily: Once in the morning at 6:30am-8am (1 hr 30) and once in the evening at 5-7pm (2 hrs). The boiler heats the water and central heating at the same time.

I got up the other morning around 7:15am for a shower. so the boiler would have been on for 45 minutes. However, the hot water was tepid. I appreciate its been cold recently but I thought after 45 minutes the water would have been up to temperature. Im normally in the shower at 7:45 and the hot water is fine.

We just got back from the in-laws this evening and the childrenwere really tired so we decided to give them a bath around 6:30pm. Again the water was luke warm (not suitable for a child's bath). So we had to put the immersion on to quickly get it to temperature.

I think it could be a number of things but looking for pointers on where to start first???

1. I heard that the radiators for the central heating may be out of balance. Could this be it? We did have TRVs fitted recently and I imagine the plumber would have had to play around with this. However, I always thought that with an s-plan system the water for the central heating just runs through the coil in the hot water cylinder which indirectly heats up the hot water in the cylinder.
2. I read somewhere that it could be the balancing valve on the hot cylinder. But Im not sure where this is?
3. Is the boiler temperature set right? We recently had it serviced and the engineer had set it to 65C so I don't think its that.
4. Could it be the cylinder isnt insulated? Is there any way to check whether it is insulated? Im pretty sure it is, house was built in 2007. But I was tempted to put some insulating jacket on the outside and on the pipes too which are bare.

Any help would be really appreciated.

youtheman

Sounds like your system needs balancing. If you don't have a zone system, and the cylinder is on the same loop as the radiators, then it looks like your radiators are taking more of the flow, and less going through the cylinder.

If the only change to your system was fitting TRVS then I'd be inclined to think it is a balancing issue. Close in the valves on the opposite side of the radiators to the TRVs. This will cause more of a restrictions on the radiators this making it easier for the water to go through the cylinder. Start by making small changes (1/4 turn at a time).

Also look at your cylinder. There should be a minimum of four pipes connected to your cylinder. One at the very top (hot water outlet), one at the bottom (cold water inlet) and another two around mid way up the wall of the cylinder. These are to the coil of your cylinder (where the hot water from the boiler enters and exits). Look for these pipes and see if there is a gate valve on one of the pipes. Open it a little bit more (again, make all the adjustments in small increments). This will make it easier for the water to go through your cylinder (and heat it up).

niallb

It should be very easy to tell if the cylinder is insulated. If it's hot to the touch it isn't!

What colour is the tank? Is it metallic on the outside or is there a sprayed on foam like later?

Fernagx

https://www.boards.ie/discussion/comment/120036602#Comment_120036602

Thanks. That's really useful advice. There is a tap/valve on the cylinder where the loop inlet/outlet is. I've opened it up slightly. Balancing the whole radiator system is probably for another day when I have time. We do have one room with a rad which we just use as a storage. I've turned the TRV right down to the 'frost' setting. However, I was tempted to tighten (not fully) the lockshield on this rad to increase flow to the other parts of the CH/HW system. Not sure if that would have any effect or if it would indeed have the opposite effect.

Fernagx

https://www.boards.ie/discussion/comment/120036650#Comment_120036650

Definitely foam. The pipes are uninsulated though. So that would make a difference.