ᐅ Challenges for MEP planners: underfloor heating flow temperature and wastewater ventilation
Created on: 15 Jul 2022 10:22
P
Pacmansh
Hello,
we are at the beginning of the construction phase for our development project with the builder, and I am having some disagreements with the MEP planner. To be better prepared for the discussion, I would appreciate your assessment.
Point 1) Supply temperature of underfloor heating, new building, KfW55 standard, air-to-water heat pump
The supply temperature of the underfloor heating (end-terrace house on both floors) was stated to me as 40°C (104°F) after inquiry. This seems absurdly high to me. Additionally, I was informed that the surface temperature is designed to a maximum of 27°C (81°F) due to the flooring materials. Somehow, this does not seem consistent. When I asked about lowering the supply temperature, the response was: "A general reduction is not feasible with the underfloor heating without reducing the pipe spacing to an unacceptable level."
Do you have any ideas how I can respond to this in a reasonably professional way? Are there any documents or sources I could refer to, or information I should request?
Point 2) Wastewater venting
Contrary to earlier agreements, this has been planned in a rather unfavorable location. The reason given is "because the wastewater vent and the residential ventilation (exhaust air) must be routed over the roof with a certain separation according to flat roof guidelines." What distance should be maintained here? A quick online search only showed a 30cm (12 inches) distance to other building components. Basically, this is about the roof penetrations and their distance from each other, correct?
we are at the beginning of the construction phase for our development project with the builder, and I am having some disagreements with the MEP planner. To be better prepared for the discussion, I would appreciate your assessment.
Point 1) Supply temperature of underfloor heating, new building, KfW55 standard, air-to-water heat pump
The supply temperature of the underfloor heating (end-terrace house on both floors) was stated to me as 40°C (104°F) after inquiry. This seems absurdly high to me. Additionally, I was informed that the surface temperature is designed to a maximum of 27°C (81°F) due to the flooring materials. Somehow, this does not seem consistent. When I asked about lowering the supply temperature, the response was: "A general reduction is not feasible with the underfloor heating without reducing the pipe spacing to an unacceptable level."
Do you have any ideas how I can respond to this in a reasonably professional way? Are there any documents or sources I could refer to, or information I should request?
Point 2) Wastewater venting
Contrary to earlier agreements, this has been planned in a rather unfavorable location. The reason given is "because the wastewater vent and the residential ventilation (exhaust air) must be routed over the roof with a certain separation according to flat roof guidelines." What distance should be maintained here? A quick online search only showed a 30cm (12 inches) distance to other building components. Basically, this is about the roof penetrations and their distance from each other, correct?
So, it remains exciting. First, the builder contacted me asking for an additional €2,500 for the extra work related to my heating change requests (additional services by the MEP planner). After a strongly worded email from me, the offer was to pay only one-third of that amount, which still doesn’t sit well with me given such a poor performance. Let’s see what comes of it.
And now the big issue:
I just received a call from the electrician (who is excellent) saying that the ventilation system has been changed. Instead of a central exhaust system, motion sensor fans will be installed in the bathroom, and a fan in the kitchen that I can switch on and off manually. Apparently, the heating installer didn’t like the roof exhaust solution and so this alternative was chosen. If I understand correctly, what was originally an automatic ventilation system with a central exhaust has now become a system with bathroom fans that only remove moisture. To me, this means window ventilation will be necessary, since the exhaust fans only run intermittently. I could at most keep the kitchen fan running continuously. Then a small fan in the duct would be responsible for ventilating the entire house. Completely absurd.
Contractually, everything is clearly stated: the roof outlets and ceiling holes for the exhaust ducts are already in place, and the fresh air supply elements for the exhaust system in the windows are also installed. Let’s see what the builder says about this tomorrow.
And now the big issue:
I just received a call from the electrician (who is excellent) saying that the ventilation system has been changed. Instead of a central exhaust system, motion sensor fans will be installed in the bathroom, and a fan in the kitchen that I can switch on and off manually. Apparently, the heating installer didn’t like the roof exhaust solution and so this alternative was chosen. If I understand correctly, what was originally an automatic ventilation system with a central exhaust has now become a system with bathroom fans that only remove moisture. To me, this means window ventilation will be necessary, since the exhaust fans only run intermittently. I could at most keep the kitchen fan running continuously. Then a small fan in the duct would be responsible for ventilating the entire house. Completely absurd.
Contractually, everything is clearly stated: the roof outlets and ceiling holes for the exhaust ducts are already in place, and the fresh air supply elements for the exhaust system in the windows are also installed. Let’s see what the builder says about this tomorrow.
So, I’m not much wiser yet, as no concrete dates were provided. If I understand correctly, they plan to install Helios ELS fans—by my estimate, four units—in the bathroom, guest bathroom, kitchen, and utility room. The bathroom fans will be controlled by occupancy sensors. However, it’s still not entirely clear to me how they intend to provide the general ventilation. The supply air will come through Aereco ZUROH air inlets installed in the roller shutter box. If I’ve read correctly in the forum, @Deliverer has also used these, right? Maybe he’ll drop by here as well. 😉
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