OT Really - TRV, Boiler and Ancillaries Recommendations

It somewhat depends if you wish to stick with just heating or whether you require aircon (they tell us there is 'global warming').

If summer cooling is required, a reverse cycle heat pump system might be of benefit.

If you might go air2water heat pump in future, might be worth thinking about making what you put in suitable, so you just swap out the heat source but don't have to upgrade the rest.

Are you planning on keeping the cylinder, or replacing that too?

IANA heating engineer but that sounds ok to me.

My installer specified Honeywell TRVs and smart controls. I've never used them but it looks like a decent 'traditional' system.

See below...

Heat pumps need bigger radiators, which aren't hugely more expensive than small ones once labour etc is included. Do a heat loss calculation and see what your actual heat demand is, and then run the radiator calcs at 45C not

If you're repiping or doing much work to the fabric, fit decent piping (22mm or more, maybe 15mm to a specific radiator) - no tiny microbore. Plastic is OK if the ID is big enough.

I've seen Wila pumps recommended for quietness, no experience myself.

Get one where you can remove the filter element without draining down, some can be done without much water coming out (I don't know brands OTTOMH, and I can't find the one that was used in an install video).

Think about what you want here - there's lots to choose from. Do you want a static pattern (always heat 9-5 M-F) or is there scope for adjusting those times, eg if the office might be empty some of the time?

You might also think about being able to remotely control: TRVs are all very well but people never adjust them. There are various 'smart TRVs' with batteries that connect to your Nest/Hive/etc, but I don't like them because the batteries go flat and they rely on wireless.

What I'd like to do is get wired radiator valves:

I'm not sure how open plan will play into that - do you currently end up with people fighting to have the right temperature (eg Alice prefers it cold, Bob 6m away prefers it warm, but since it's open plan Bob turns up his TRV and Alice opens a window)? Seems tricky to handle a temperature gradient like that in a big space - a traditional TRV and single wall thermostat seem like a poor solution.

Have you asked the users if there's anything the current system lacks or could do different, from their perspective? You might find 'shadow practice' where people work round things that don't do what they want, like leaving the window open (which might also be due to poor ventilation).

Theo

That is a pretty large boiler (about 36kW)... you may be able to get away with something a fair bit smaller (say 24kW)

So S Plan+

Would be handy if it's something that can understand multiple heating zones out of the box. E.g. a Vaillant system boiler.

There are a number of fairly decent clones about of the TRV4s now. Might be worth asking a local plumbers merchant what they think is good... I did that when I did my last heating system refit, and the (clone) TRVs have worked flawlessly.

If going for a sealed system, then fit a system boiler. No need for a separate pump then.

A filter - yes essential if retrofitting into an old system of questionable cleanliness. (although obviously flush everything well first using the old system before you decommission it). The fit the new and flush again.

I rather like the Fernox TF1 - same kind of idea, but better design all round IMHO.

If going for multiple zones, then its cheap to add weather compensation[1] as well. That makes for a quieter and more comfortable system - especially in the "part" load bits of the season.

I remember 50 years ago finding out that there was no maximum temperature for office staff. The computer had air conditioning but the room with the keypunch operators did not and with the machines it could get hot in the summer. It looks like there is still no max temperature.

BTW is this the same building as has your server room (mentioned in your other question)? Perhaps you could duct/pump heat from there, since you're presumably putting lots of power into your IT kit? That would give you 'free' heating - just pay for moving it around.

Theo

I had a protracted dialogue with site services because of problems with the office aircon system - I eventually convinced them that having no user controls wasn't working. There seems to be little understanding that you need accurate control, but quite a large band between heating and cooling, and the way this was working, winter and summer settings needed to be different.

So, they gave us a small control panel, which also showed us the state of the three heating stages. Even when all three were on, especially on a cold Monday morning, there were those who insisted on winding up the setting. This was, for added irony, in an office full of professional control engineers.

Chris

I've always thought that the temperature should be set to what the person in the workplace who likes it coolest needs to be reasonably comfortable. Those that like it hotter can put more or thicker clothing on, the one that like it cooler can't do much about it if they are too hot.

Thanks Jack

We already have Air-con. In some offices this is capable of heating. But we really need a heating solution that can be used which doesn't circulate germs around the office atm.

Phil

It is not just the set temperature that matters. If the airflows end up meeting from adjacent outlets, the result is apparently called a "cold dump". Having had the misfortune to sit beneath one, it is not fun.

I recall one hot summer where I sat at my desk with my jacket on throughout, but had to remember to leave it behind if I stepped out to the factory floor.

Chris

Good question - I was kind of expecting to ditch the cylinder and go combi, but forgot to mention that bit!

That's a good call - they are likely to need to go up in size anyway if the condensing effect is to be optimised.

The piping looks pretty good to be fair - 22mm fairly local to rads,

I thought they were all capable of isolation - I have MagnaClean at homea and that is isolatable.

Probably likely to be pretty static requirement.

That sounds a little more complex than I had anticipated but will try to keep an open mind.

There's an element of different requirements in adjacent areas. I think the biggest issue is old draughty windows - the wooden frame type with

Asking users sounds good in theory, but can lead to a lot of disappointed staff when you can't meet their exact(ing) requirements for whatever reason.

Thanks for the input Theo

Phil

From a solely heating point of view, you may be right John, but I forgot to mention the probable introduction of combi heating. Also, I am not sure how to carry out heat loss calcs when there are draughty windows involved.

Yes, with or without cylinder

Not sure what you mean by that. How does the boiler understand multiple zones or cater for them? Does it just provide a wiring centre that will support connections for these?

Will investigate thanks

OK

OK

Will investigate thanks

At present, I am only anticipating one zone to each floor - would weather compensation still make a difference here?

Thanks for your input John

Phil

When I first read this I thought genius! Unfortunately (in some ways) most of the equipment housed in the current server room will be going, as business and services move to "the cloud".

Combi as in combi boiler or some other meaning?

(note that most high power combi boilers will only deliver their full output for heating DHW and not driving rad - so a 35kW combi may still be limited to 24kW to the heating)

Ideally after draft proofing!

However you count them by introducing the concept of "air changes" per hour.

System boiler and unvented cylinder make a good pairing, but then again for a commercial premises you may not have much demand for hot water.

The controls are hooked up to their eBus network, and so can communicate in a more sophisticated way than just closing contacts on the "call for heat" input of the boiler. The programmer (and matching wiring centre) can control more than one zone, and you can time them separately etc.

So for example on mine, it has sections for upstairs, downstairs, and hot water. It takes input from the stats in each zone as well as the external one.

Yup, especially in the milder parts of the year where you don't need much heat input. The system just ticks over running low flow temperatures - keeping condensing efficiency up, and gas consumption down. On cold days it will also ramp up the flow temp to ensure you can still get the place warm in a reasonable time frame.

(I can tell if it is a really cold day when I wake up just by listening to the rads and pipes - if you can hear lots of ticking and clanking as things expand and move, then you know the boiler is running higher temps because its really cold out!)

On thing to bear in mind is bigger radiators hold more water, so might increase the lag it takes for the system to respond to a call for heat. Although you aren't heating the water as hot so it's perhaps mitigated that way. As you say, a condensing boiler is more efficient at lower temperatures so they aren't just for heat pumps.

Surely you mean the other way? 22mm 'trunk', 15mm 'branches'? Or the branches are larger for cosmetic reasons?

In open plan you might also think about how the multiple TRVs interact - if radiator 1 turns on, radiator 2 sees the temperature rise and so turns off. Meanwhile the air around radiator 1 has warmed up so it turns off, but then everything cools and the radiators turn on again. You might end up with unexpected feedback in the control system which isn't served by individual TRVs mounted close to the ground and the radiators.

I don't actually know if the UFH controller is the right thing here - they're used to controlling on zone per room - but it seems something with a more holistic view of what's going on would be useful. I don't know the right product for that, but I imagine they exist in the commercial building market.

How feasible would it be to replace the windows? By fixing that problem you'd need a smaller heating system and reduce your running costs. You can always open then for ventilation, or there are other options (eg MHVR) if you want to go fancier.

It would be unfortunate to fit an enormous heating system, and then next year replace the windows and find it's running inefficiently as it's oversized.

Perhaps. Or maybe just an anonymous survey or something?

I imagine it's not uncommon for institutions to be inhabited by people whose opinions of the system are rather different to those of the building maintenance people who set it up. If you get users on board you're less likely to have shadow practice like opening windows when the heating is on.

Theo

That was my wording...

I think that when the system actually worked (many years ago before the TRVs started failing) there might have been an element of this. But it seemed possible to get an overall fairly stable temperature that users were happy with.

Unfortunately, we are now under the "management" of folks that are not local, so spending money for future gain tends to be frowned upon.

It may well be necessary to consider heating on and windows open to maintain a reasonable Covid-unfriendly space, unless air to air heat exchange is thrown into the mix.

Thanks for your input Theo

Yes

I did not know that thanks.

The current window casements actually have a seal, so I'm not sure how that would be achieved, for some of them, they just don't meet the frame. Maybe fit a bigger seal.

Good call :)

Sounds like a plan

Is that a programmer integral with the boiler?

Understood - thanks for your input John

Yup there places that have a great catalogue of different sealing profiles for this kind of application.

So a combi may well be adequate and cheaper - although not sure how many will "understand" multiple heating zones out of the box with the same level of sophistication you can get with some system boilers.

Some of this will come down to location - if the boiler is a long way from the points of use, then the lag to get hot water there might be annoying, and a small unvented cylinder closer to the point of use would be better.

You normally buy it as a separate thing... e.g: