Full Vaillant System, please spec me controls.

[chipperhead]

I'm specing up a total new CH System and going for a Ecotec Plus 637 and a Unistor 260 cylinder.
My only query is regarding the control, I have a 1920's detached house and have read that a VRC400 works best in a well insulated house, although we have done our best, ours isn't upto a modern house for insulation. Would it be still worth fitting?

Also I have searched this forum and have seen that you put the VRC400 into a dry pocket on the boiler and use TRV's on every radiator.
If I am putting the boiler in my garage, would I have to go into the garage to control the heating.
Thanks

 

[joncox]

We are in the process of having a VRC 430 fitted (with Ecotec 618 and 155 Unistor - it's a smaller house). The 430 is the updated version of the VRC 400 you mention.

After discussions with my installer and advice from Vaillant installers here, my understanding is that it's *most efficient* if you have a well insulated house.

The better insulation you have, the flatter the heating curve you can choose in the configuration of the weather compensator. Poorer insulation = steeper heating curve

I have been told both by my installer and on here that is better to have the unit wall mounted (in hall in my case) rather than on boiler as then you can monitor room temp as well as outside temp.

To answer your question - yes you would have to go into the garage to adjust temp from the programmes.

 

[chipperhead]

We are in the process of having a VRC 430 fitted (with Ecotec 618 and 155 Unistor - it's a smaller house). The 430 is the updated version of the VRC 400 you mention.

After discussions with my installer and advice from Vaillant installers here, my understanding is that it's *most efficient* if you have a well insulated house.

The better insulation you have, the flatter the heating curve you can choose in the configuration of the weather compensator. Poorer insulation = steeper heating curve

I have been told both by my installer and on here that is better to have the unit wall mounted (in hall in my case) rather than on boiler as then you can monitor room temp as well as outside temp.

To answer your question - yes you would have to go into the garage to adjust temp from the programmes.

Thanks joncox for the info , we have cavity wall insulation and loft insulation etc but bigger older houses can be just draughty.
Think I'll definately go for this setup with the VRC 430 situated in my hallway. Are you purchasing a VR65 aswell and putting TRV's on all your rads except the one were your VRC430 is?
Have you purchased anything else to go with this set up?
Thanks.

 

[joncox]

Yes: we will have a VR65 to interface between boiler-cylinder-exterior sensor-wall unit.

Yes: new TRVs on all rads except hall

We are having some other minor stuff (new cold feed and spur for dishwasher, towel rail in bathroom), but nothing further from Vaillant. There will be a Magnaclean too, impt if you are using existing pipework to rads.

First you must make sure of two things:

1) you have enough static pressure and flow to make the Unistor worthwhile. We are lucky enough to have 6 bar and almost 30litres/min.

2) Easily accessible exterior north wall for sensor

 

[chipperhead]

We're having all new pipework, haven't thought about Magnaclean but probably not needed, might look at an anti limescal inhibitor as we live in an extremely hard water area but I don't know if they actually work yet.

Will your towel rail be piped in on the Central Heating circuit? Reason I ask is currently ours is on the hotwater so even in summer, twice a day our towel radiator gets hot. Speaking to my plumber, I don't think its going to be practicle to do that again as the boiler and tank will be next to each other in the garage at the opposite side of the house.

I used the fill bucket test and calcualted 32l/min so fine there and also the garage has a north facing wall.

Just been reading the instructions for the VRC 430 and are you aware regarding the fitting of the Weather Compensator:

"On buildings upto 3 floors, the outside sensor should be fitted at the 2/3 floor facade height, on buildings with more than 3 floors , mount between the 2nd and 3rd floor"

I'm not 100% sure what this means, how do you read it?

Thanks for your responses, you've been a great help.

 

[joncox]

1) 32l/min is good but I would suggest a pressure gauge as well. If your installer can't-won't (worrying) then you can buy one for a tenner from an merchant. They screw onto an exterior tap.

2) The wording is rubbish. Our installer says it's because the Vaillant manuals are all translated from the German.

I think it simply means that you need to mount the sensor at least at 1st floor height. Ours is going on the exterior wall at the back of the airing cupboard, about 4m off ground. I presume your garage is single storey?

3) We will have towel rail teed into DHW circuit rather than heating, yes. Pipe run will be short and straightforward for us

 

[chipperhead]

Our garage is single story but slopes with the main roof so that won't be a problem.
Thanks for your help, think you've answered everything, for now anyway

Hope your install goes smoothly.

 

[gas4you]

I personally always boiler mount the VR400/430, then have trv's on all rads.

The VR400 does not go into the dry pocket on the unistor, you need to buy the VR10 for this.

The VR10 connects into the VR65, along with the ch & dhw zone valves.

The VR65 is connected to the VRC 400 and/or the boiler via the ebus system.

To use the VR10 you have to completely remove the supplied cyl stat that is fitted on the unistor.

Only use the VR400/430 if you have access to a north wall.

Note also that you can only have one heating zone with the VR65.

 

[chipperhead]

Thanks for your reply Dave.
I'd be greatful if you can advise me to what you'd spec me up.
Also I will be going for underfloor heating, let me sum up my situation below, we will be living in this house for many years so initial cost isn't too much of an issue also my towel radiator is currently fed from the Hot Water side of things but my towel radiator is at the opposite side of the house from were my new boiler and cylinder will be situated.

5 bedroom 1920's Detached House
2 Bathrooms
14 Radiators
1 towel radiator
Underfloor Heating area roughly 17.5m2

Thanks.