How to control inside temp of a domestic floor's bathroom which is equipped with radiant wall heat ?

Roohollah

Dear Members ,

We are going to install a hydronic radiant wall system for a residential floor's bathrooms and radiant floor heating for rooms and living rooms as well . There are a pair of low temperature lines ( supply and return ) from a central heating system to serve this floor which we have piped since earlier years . This floor is constructing at the moment and it is the fourth floor of a four floor building .

Our plan is to install Uponor radiant floor heating for all rooms and radiant wall heating for two fairly commodious bathrooms . As for towel warmers , the dedicated heating lines are carrying low temps ( max 113 degrees Fahrenheit ) and we think that such temp could not heat up the baths during hard winter over there . Also, their floors are occupied by massage tub , cabinet type lavatory ,and toilet and there is not enough empty place for considering radiant floor heating .Thus, the idea of radiant wall comes into our mind and it is possible to install ,but our big concern is how to control the bathrooms' inside temps whenever their temps exceeding our demand ?


As for other areas , they will be controlled by room thermostats ;however, as the bath relative humidity is high and low IP electrical devices are forbidden to install inside there we were wondering if you could mind assisting us how to do the job with possible solution .



Thank you in advance for taking the time to consider the subject and your support,



I look forward to hearing from you ,


Sincerely,

Roohollah

Mark Eatherton

If you want to maintain the current plan of low voltage electric thermostats controlling zone valves and end switches, you could place a sensor in the final finish material (sheet rock) and control it remotely from the mechanical room. Place the sensor between two tubes, and then set the set point for around 75 degrees F. It won't be accessable fo people to touch in the bathroom, which will hopefully meet the code intentions. You will have to play with it's setting to fine tune it. If that is not an option, then I'd look at a non electric thermostatic radiator valves.

Numerous manufacturers including Honeywell, Dannfoss, and Oventrop. I know Oventrop makes a remote controller with a 10 meter (33 foot) long capillary tube. (I see an ad for Oventrop flashing to the right hand side of this column)

The only problem with non electric controls is that it may require you to establish a constant run condition for your circulator and a rest program for the heat source. If the whole home were done in non electric TRV's, you'd have to do that anyway, but with electric controls, it's not usually a requirement because of the end switches making calls for heat as needed. You can try it without the constant call and see how it works, and if it doesn't work well, set the heat source and distribution system up for constant run on the pumps with outdoor reset.

If you are using a constant/fixed speed pump, you will have to incorporate a means of pressure activated bypass to avoid dead heading your pump. If it is variable speed based on delta P, you need to do nothing. The use of TRV's is a proportional control. If the rooms needs just a little heat, the valves opens just a little bit. If the room needs a lot of heat, the valve opens wide open, but as it approaches its set point, it modulates closed.

You're going to love the comfort associated with radiant walls. I have them in three of the houses I own, and I LOVE them, even in front of a large couch. Don't forget the ceiling too.

ME

Roohollah

ِDear Mark ,

I would like to express my gratitude to you for such excellent post which composed of many useful and technical points .

I have decided to use Uponor pe-pex pipe for wall radiant with its engineered polymer manifold and as you know better , every zone controls by its own actuator valve ( 230 V) . The rooms will be controlled by room thermostats and bath room with remote controller as you stated precisely above .I will research Honey well brand remote controller because it may be available in our area .

This my second time experience to install wall radiant heating . There many lessons that I must learn . Thank you all for assisting me whenever I come across difficult situations .


I do appreciate your post and time ,


Yours Sincerely,

Roohollah

Mark Eatherton

My pleasure Roohollah. Enjoy the job and the comfort you will be delivering.

ME