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I've been in denial about this for a long time - out of sight, out of mind, but I do need to know what I need to do about it so here goes ...

 

Hubby installed MVHR in the house. I've never seen the actual unit and I still can't see the actual until as for some reason it's been installed in the loft and not in the room where the boiler and TS are. It seems that Rega Vent (where it was puchased) created the spec and specified a loft mounted unit so that's what it is. 

 

I've dragged out what documentation there is but there is very little that I can find. No manual for the unit so pictures will need to tell the story. 

 

The main issue is that I can't get to the unit if anything needs to be done to it now or in the future to service it. The system was installed back in 2009 so it will be old technology no doubt. 

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The only controls seem to be in the boiler room as pictured. 2 speed controllers. Because I’m not sure what each does I always set them the same. There is also a switch to turn the whole thing off. Well I assume that’s what it does but don’t know for sure! The switch is below the controls. 

 

According to the list of components purchased there is a summer bypass unit but how that gets switched off and on I’ve no idea! 

 

 

 

 

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The technology has not changed any.  Some are better than others that is all.

 

Basically warm, moist air is drawn out of the house, the thermal energy is extracted by the heat exchanger to warm up cooler external air that has a lower humidity.

Sometimes the outside air is warmer than the internal air, and sometimes the external RH is higher too.

That is when the control system earns it keep.

So the important part is the control system really.  The heat exchanger is in a box with a couple of fans connected to it (usually).

Edited by SteamyTea
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Outside there seems to be 2 vents as pictured plus a ventilation tile on the roof. Not sure they are all related to this? I can hear it doing ‘something’. 

 

Upstairs I can see that one of the vents has a pipe next to it. I assume that’s a drip pipe or something? I can hear lots of ventilation type noise coming from the vent furthest away (pictured) but nothing at all from the nearer one with the pipe. 

 

 

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Inside there are the normal room vents as pictured and the main unit in the loft that I can’t even see apart from what I assume is the main switch for it. There is zero chance of me being able to get to it. 

 

So my questions are:

 

I assume that it should have had some maintenance in 9 years although that will be an issue if I can’t get to the main unit?

 

How do I know if it’s working? 

 

What settings should i have it on and are the switches likely to be upstairs / downstairs?

 

Any clues where summer bypass might be located? Could that even be the white switch in the boiler room that I thought was to switch the main unit off and on? 

 

The silver and black insulated pipes up there are something to do with it I imagine? 

 

Not quite in the same league as my heating nightmare but still something I have no clue about. 

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26 minutes ago, SteamyTea said:

The technology has not changed any.  Some are better than others that is all.

 

Basically warm, moist air is drawn out of the house, the thermal energy is extracted by the heat exchanger to warm up cooler external air that has a lower humidity.

Sometimes the outside air is warmer than the internal air, and sometimes the external RH is higher too.

That is when the control system earns it keep.

So the important part is the control system really.  The heat exchanger is in a box with a couple of fans connected to it (usually).

 

Thanks. It is what it is, I’m not planning on changing it, but at present I can’t get to it :S

 

 

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2 minutes ago, SteamyTea said:

Why do you want to get to it.  Apart from initial setup and changing any filters fitted, they don't need to be looked at.

 

Because don’t I need to change the filters at the very least? I read on another thread that they should be looked at every 3 months. And the description mentions ‘condensate drain’. Shouldn’t that be checked or is that what the thin pipe is for? 

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50 minutes ago, SteamyTea said:

Why do you want to get to it.  Apart from initial setup and changing any filters fitted, they don't need to be looked at.

 

 

There's a building regs requirement for it to be easily accessible for servicing, plus the filters need to be cleaned/changed at least every six months (sometimes more frequently), and some models require a regular check and clean of the heat exchanger, too.

 

The intake filter on ours needs cleaning at least every six months, and ideally perhaps a bit more frequently than that, as it doesn't take long to get clogged up.  Our unit has a filter alarm that shuts the MVHR down if ignored, and the longest filter change interval that can be set is 6 months.

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8 minutes ago, JSHarris said:

There's a building regs requirement for it to be easily accessible for servicing

 

Building control didn’t even look at it. 

 

I guess ideally I’d need the loft to be boarded in a path to the damn thing. I assume that’s easier than putting another loft access in next to it? 

 

 

 

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Interesting, as my building inspector asked for a commissioning report that showed that it had been installed, tested and all airflows measured and balanced in accordance with the regs - my guess is that there's an inconsistent approach to applying the regs...

 

You do need to get access to at least be able to regularly check/clean/change the filters.  I find that the intake filter on ours is full of crud after 6 months, and I probably need to get into the habit of cleaning it more regularly.  One reason the building regs insist that there be easy access to these units is because of the regular servicing requirement, so boarding out a pathway to it would be a good idea.

 

 

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1 minute ago, JSHarris said:

Interesting, as my building inspector asked for a commissioning report that showed that it had been installed, tested and all airflows measured and balanced in accordance with the regs - my guess is that there's an inconsistent approach to applying the regs...

 

You do need to get access to at least be able to regularly check/clean/change the filters.  I find that the intake filter on ours is full of crud after 6 months, and I probably need to get into the habit of cleaning it more regularly.  One reason the building regs insist that there be easy access to these units is because of the regular servicing requirement, so boarding out a pathway to it would be a good idea.

 

 

 

Thanks. I will need to see about getting someone out to sort that then, if that's even possible given how difficult it is to get trades in to sort anything out at all here. It looks like it's in a nightmare part of the loft with no headroom at all so may be a crawling on knees job to service it :S

 

I knew I had to get round to addressing it one day. If only it was in the boiler room 9_9

 

 

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I wired one 18 months ago that was in a tiny loft of a mostly vaulted roof. I said at the time it would be impossible to get to to service the filters but nobody seemed to care.

 

What you (or somebody) needs to do is make a walkway from the loft hatch to the unit (when you find it) so you (o someone) can get to it to change or clean the filters.

 

I would leave this until the autumn. You will find people "less than enthusiastic" at wanting to do an awkward job in a very hot loft in this weather.

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8 minutes ago, newhome said:

 

Thanks. I will need to see about getting someone out to sort that then, if that's even possible given how difficult it is to get trades in to sort anything out at all here. It looks like it's in a nightmare part of the loft with no headroom at all so may be a crawling on knees job to service it :S

 

I knew I had to get round to addressing it one day. If only it was in the boiler room 9_9

 

 

 

 

I deliberately put ours in the services room, so access is easy, just walk into that room through a door from the spare bedroom.  There's even a carpet on the floor in front of it so kneeling to check the filters is easier on my knees!

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1 hour ago, ProDave said:

 

I would leave this until the autumn. You will find people "less than enthusiastic" at wanting to do an awkward job in a very hot loft in this weather.

 

@newhome I have it on good authority that @Nickfromwales loves working in attic spaces at this time of year - something to do with a diet ....

 

As @JSHarris said though, needs a decent route to get to it and the filters may not need cleaning if it hasn’t been run ..!

 

you may hear something from the exhaust fan as that will project noise outwards - the intake may well be quieter. 

 

And as for tracing wires, you know who’s best at that ..!

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47 minutes ago, PeterW said:

 I have it on good authority that @Nickfromwales loves working in attic spaces at this time of year - something to do with a diet ....

 

He could wear that that rubber suit up there. I’m sure that’ll be good for the sauna effect or sumit :D.  

 

I’m sure it was switched on for a few years tbh. 

 

My plan for ascertaining whether the switch in the boiler room was for power to the unit or just summer bypass was a bit more simple than tracing wires. It goes like this. 

 

Turn off MVHR at the CU. Listen to see if fan stops. Switch back on and ensure fan is running again. Then turn off the switch in the boiler room. If the fan is still running then it’s the summer bypass switch, if not it’s the switch for the main unit.

 

Thoughts? 

 

 

Edited by newhome
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Don’t think so as all of yours is marked up (like a good boy). It has something written above it that implies it’s for this. 

 

So so I did my little experiment. Off at CU fan noise stops. Switched off at wall, fan sounds the same as when it’s switched on at the wall so the switch does nowt, does something different, or does summer bypass. Now how to tell? 

 

Whatever it does, or not, it’s clear that the unit has been on for 9 years and counting. 

 

 

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Would the summer bypass just either push air into the house, or suck it out.

If so, then maybe the exhaust has no airflow, but the intake from outside does, or visa versa.

 

I assumes the loft was properly boarded to get to the unit.  All PV stuff that was fitted in lofts had to have a pathway and a standing area.

I don't understand why newbuilds don't have the loft boarded by default, that way the insulation can be covered over and no one will know it is missing.

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28 minutes ago, SteamyTea said:

Would the summer bypass just either push air into the house, or suck it out.

If so, then maybe the exhaust has no airflow, but the intake from outside does, or visa versa.

 

I assumes the loft was properly boarded to get to the unit.  All PV stuff that was fitted in lofts had to have a pathway and a standing area.

I don't understand why newbuilds don't have the loft boarded by default, that way the insulation can be covered over and no one will know it is missing.

 

I thought the summer bypass just bypassed the air being brought into the house being heated? Might be wrong .....

 

The loft wasn't boarded to get to the unit or install it. I'm pretty sure hubby just walked along the joists just as he did when he installed the downlighters and the loft lights. The difference being that there is no way I will be walking along the joists to get to a unit that looks as if it's going to be at ground level in an area with no headroom :S

And I'm with you - I don't know why the lofts aren't boarded by default. Our old loft was (hubby did that) so why not this one, especially as there is something up there that needs to be accessed. Maybe I could just shove a few boards up there and nail them down roughly? Dunno. I could probably do that down the middle where the access is clear but what the hell do I do here? 

 

That switch attached to the wood and the lead that comes out of it will lead to where the unit will be I think. 

 

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Edited by newhome
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My normal approach to these is to build them out of OSB or anything else around, precut them and install across the joists above the first layer of insulation, the; put the next layer on top to be removable, and put a notice by the loft hatch.

 

And drill the arrangement into tradesmen quite firmly.

 

But that keeps the heat loss down. 

 

Yes to screws.

 

F

Edited by Ferdinand
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By complete coincidence, the change filter alarm on our MVHR came on this morning, so I've just been in and changed the filters for new ones.  This photo shows what an intake F7 (pollen) filter looks like after 6 months use, compared with the new intake filter below:

 

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