Ventilation Boost switches

[JFDIY]

Or have them activated from light switches.

 

You either need double pole switches or my plan of using a UFH wiring center with relays to have the light switches as the input and the boiler run output to the MVHR boost.

 

If you don't separate the switch inputs the turning in the lights in one bathroom will put them on in other linked rooms.

 

 

Then of course a PIR sensor in each room would work too.

 

In practice if the MVHR unit has a humidity sensor in it you may will find you don't need the extra inputs, mine seems to work quite well by itself in this respect so far.

[Jenni]

Thank you everyone. 

[Roundtuit]

12 hours ago, JFDIY said:

In practice if the MVHR unit has a humidity sensor in it you may will find you don't need the extra inputs, mine seems to work quite well by itself in this respect so far.

Our unit has a humidity sensor and it does the job really well when showering. It's also proportional, so ramps up and down as necessary.  The only reason I'd use the boost switch would be after a curry and Guinness night, but even that hasn't been necessary.  Too much information...?

[Bonner]

10 minutes ago, Roundtuit said:

Our unit has a humidity sensor and it does the job really well when showering. It's also proportional, so ramps up and down as necessary.  The only reason I'd use the boost switch would be after a curry and Guinness night, but even that hasn't been necessary.  Too much information...?

 

... no, that is useful public information thanks ?

anyway, which model? Is it an internal or external sensor?

Sensor control is good for managing humidity levels but I would install a manual boost switch for aforementioned reason

[Roundtuit]

Ventaxia kinetic sentinel B I think.  The in-built humidity sensor exceeds my expectations; you only need the shower on for a few minutes for it to kick in, then it just drops off when it's ready.  We put in the boost switches in case we needed to 'clear the air' (and, from memory, to help satisfy Building Regs) but in reality, they're never used.

[markocosic]

I've got a flow sensor on the hot water from the boiler; and set this to trigger a boost on the MVHR (a Triton unit) if it's used for more than a minute and to run on for 5 minutes afterwards once triggered.

 

This is faster to respond to showers than humidistats and clears the steam before you've filled the bathroom rather than afterwards as it were. (important if you have a decent shower in a small bathroom that's very tiles/has very little vapour buffering) 

 

Unlike a light switch it doesn't boost when not needed and the regular extract (only one bathroom in the "house" on the MVHR, with the other in the "addon porch") is enough to deal with regular loo smells. Exceptional smells are banished to the "addon porch" by the wife. 

 

In hindsight...

 

I should have made provision to put this on the hot water feed to just the shower rather than to the entire house...as the hot fill dishwasher also triggers it.

 

I would add a manual boost for curry night if you don't have the luxury of a large house. (this place is only 70m2)

[readiescards]

On 09/05/2021 at 21:22, Roundtuit said:

Ventaxia kinetic sentinel B I think.  The in-built humidity sensor exceeds my expectations; you only need the shower on for a few minutes for it to kick in, then it just drops off when it's ready.  We put in the boost switches in case we needed to 'clear the air' (and, from memory, to help satisfy Building Regs) but in reality, they're never used.

 

That's interest.  Very very rarely does the built in sensor kickin.  My utility/clothes drying room is a long way from the Sentinel Kinetic MVHR, so I ran double pipe work, but often it feels 'steamy' to me but the boost does not kick in.

 

For the wet rooms, have to manual kick the boost in, using a (long) momentary push of the boost switch (I have the unit in control mode 2 with the link install - I think) 

 

[dpmiller]

the humidity threshold for the internal sensor should be adjustable in the menu.

[Roundtuit]

We're just on factory settings, and it's activated pretty quickly by both wet rooms.  One extract is right over the shower, but the other is about 3m+ away.  We dry stuff routinely in the utility room, but I don't think there's enough 'steam' in there to activate the boost.

[Adsibob]

I’m just in the process of designing my extraction and supply ducts. Should extracts be as close as possible to a shower, or is there benefit of balancing its position beben the shower and the WC? 

[Jenni]

BPC advised me to definitely not site the extract directly over the shower cubicle. 

[Roundtuit]

On 21/05/2021 at 07:32, Jenni said:

BPC advised me to definitely not site the extract directly over the shower cubicle. 

Not in a cubicle I can understand, as it might restrict air flow, but I can't see why it would be an issue in a 'wet room' type situation?

[Nickfromwales]

Cubicles are typically 1850mm high in rooms with 2400mm ceiling heights. Why would there be any restriction of airflow ?

[AliG]

As installed our system has humidity sensors and automatically boosts. From watching it it seemed to me that the outside humidity level has a lot higher impact on whether the boost comes on than if someone has had a shower.

 

In the end I just turned off the function as I felt it just caused the system to run at a higher speed more than was necessary. First I raised the humidity boost point, but in the end just turned it off.

 

I then set it n a programme for speed 1 most of the time and speed 2 a couple of hours a day when people were most likely to shower.

 

Then I decided it was all unnecessary and just set it to the lowest speed all the time, except when summer bypass kicks in.

 

I think unless you notice loads of steam and humidity after a shower it will be fine. In fairness I wonder if it depends on the volume of your house. The regs allow for the same amount of ventilation no matter how big and how occupied your house is, presumably allowing for a worst case scenario. A shower in a 700sq foot 2 bed flat is going to have a lot more impact on humidity than in a 3000sq foot 5 bed house.

[Nickfromwales]

Quite relevant for the vents to be opposite the door eg as far away from the entry / exit point of the airflow. I notice a lot of design from ventilation companies put the vent where it’s convenient vs where it would benefit the room most.

Air will follow the path of least resistance so having a vent near a door will leave a lot of the room ‘stale’. 
On a current project I’m putting ‘ablution’ retractive ( press and release ) switches in the cloakroom, en-suite and master bathroom to initiate boost, and also in the kitchen. The idea is, to temporarily boost the MVHR according to ‘foreseen events’ but, in honesty,  I think the most effective will likely turn out to be the one in the kitchen.

The Brink unit will allow me to connect to a set of zero volt contacts to initiate a factory definable 5 minutes of boost. That’s ok for the bathrooms, eg for when someone gives birth to King Kong’s thumb, but for the kitchen I am

going to put the switch onto a timed contactor which will latch on for a set period of time ( after a single press and release of the kitchen ‘boost’ switch ) and try that at 1hr and see how it goes. Idea is, if the client throws a fry up on or some kippers, the system is set up to prevent the smell escaping the kitchen area vs curing the problem AFTER it’s happened. 
Quote relevant in the more open-plan swellings I seem to be working in quite often. Maybe not so problematic in a separate / enclosed kitchen but deffo worth the effort in open-plan IMO. 
We’ll wait and see what the feedback is, but it’s not big money to execute so a worthwhile bit of insurance afaic. 

Edited May 23, 2021 by Nickfromwales

[Pocster]

1 hour ago, Nickfromwales said:

That’s ok for the bathrooms, eg for when someone gives birth to King Kong’s thumb

Photo ?

[Nickfromwales]

41 minutes ago, pocster said:

Photo ?

You’ll have to email Norris Mucksquirter @guinessbookofrecords for copies. 

[markocosic]

Interesting @Nickfromwales

 

Dampers might also be fun in the 'open plan kitchen' scenario - dampers to deliberately unbalance the MVHR by opening up the kitchen more than the bathrooms; to create a net flow towards the kitchen rather than there being an equal suck on the kitchen side and the bathroom side of any open plan area.

 

Dad had a system back in the 80s (!) where the kitchen extract hood was integrated with the MVHR. There was a damper in the extract hood such that 'normally' it had a small hole and was evenly balanced with the bathroom extracts / room supply. When you 'turned on the extractor' (which had no fan of its own) it boosted the MVHR unit and opened a damper within the cooker hood so that it had a 6" hole not a 2" hole. (it wasn't a fire damper)

 

The HX was a metal affair that REGULARLY had to go through the dishwasher courtesy of grease + dust (not a good idea running kitchen hood extract through the MVHR unit). The idea of "unbalancing" the MVHR to prioritise the "general kitchen extract" in an open plan setting probably has some merit though.

[Nickfromwales]

The cooker good should never discharge directly into the MVHR as that will cause grease etc to contaminate the ductwork and filters. 
Dampers in the duct was an early idea of mine, but doing so would make the system far more audible in normal use so I abandoned that idea tbh. 
Cooking steam / grease / odour should be caught as soon as practicable, by a charcoal filter, and strategically recirculated back into the kitchen area for final removal via the MVHR ( in an ideal world ).