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Water not circulating fast enough hydronic heating system

Allous
Allous Member Posts: 4
in Radiant Heating
Hi, 
I need your help, I have hydronic central heating system with forced air.
The hot water run through the coil and air blown at it gain temperature and circulate through the house.
I live in Canada, the temperature now is -6 degrees Celsius. Inside the house the temperature is 20 degrees Celsius and air temperature that is being pushed out is only 25 degrees Celsius.
I tried purging the system by draining the cold water coming out and the air temperature coming out rose instantly by additional 7 degrees Celsius. That lead me to believe the hot water is not circulating fast enough inside the heating system maybe.
I have a hot water tank and the water is heated by natural gas 

Comments

  • mattmia2
    mattmia2 Member Posts: 11,113
    That is a real hack job of an install. Did it ever work right?
    SuperTech
  • Allous
    Allous Member Posts: 4
    Yes, it did last year
  • SuperTech
    SuperTech Member Posts: 2,492
    That's a terrible installation.  It really needs to be redone properly.  You most likely have a an air problem but I don't know of any quick fix for that mess.
  • Allous
    Allous Member Posts: 4
    If I have someone come to fix this installation, what will we the proper way to fix it ?
    O you know what could be the cause of the system not heating the house enough?
  • jesmed1
    jesmed1 Member Posts: 834
    One basic problem is that the system appears to have no way to bleed trapped air out. Air in the system will interfere with water circulation and cause symptoms like you are seeing. So at the very least you need someone who understands hydronic heating systems and will replumb it with a way to get the air out.
  • Hot_water_fan
    Hot_water_fan Member Posts: 2,077
    Is this water heater what you also use for domestic hot water heating? 
  • Allous
    Allous Member Posts: 4
    yes, we use this water heater for our domestic hot water needs
  • Hot_water_fan
    Hot_water_fan Member Posts: 2,077
    yes, we use this water heater for our domestic hot water needs


    1. Water coming from the street has air in it, so you will need a way to continuously remove it
    2. Is everything rated for DHW? The typical heating circulator is cast iron and IS NOT appropriate for this set up. You could be lead poisoning yourself, it's serious.
    Allousmattmia2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,676
    edited November 2023
    The water heater is designed to heat Domestic Hot Water. It is considered an open system. The highest temperature setting on a water heater is about 60°C and there is always the possibility to have air form in the system piping when the cold feed water is heated. Not the best device for a closed system Space heating unit like your HiV air handler.


    A boiler designed for Space Heating is usually a closed system that operates at a lower pressure. Once the system is filled with water and purged of air, the closed system recirculates the same water over and over again. That water is not for for human consumption. The boiler temperatures can be set at 83°C or higher. (in some cases over 100°C at 10 PSI). That hotter water will certainly heat your home.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Allous
  • mattmia2
    mattmia2 Member Posts: 11,113
    edited November 2023
    One of 3 things is happening.

    1. There is air from the water that has settled in the hydroair coil and it is now air locked.
    2. The water heater is scaled/filled with sediment to the point it doesn't have enough capacity anymore.
    3. The circulator isn't working and you are just getting gravity flow. (this is unlikely because the check valve probably provides enough resistance to stop gravity flow.) BTW that is a bronze circulator designed for use in open systems. The water in the coil growing legislation and such is a potential problem however.

    It is hard to tell from those pictures and with pipes running every which way, but it looks like that new valve at the upper right in the picture of the water heater is a purge valve. Try opening it and letting a couple gallons flow through it and see if it solves your problem.

    To rule out the water heater losing capacity, try running the hot water while the coil is running, see if it is as hot as it normally is.

    This looks like it has been worked on by several people who didn't care about following code or professional workmanship but I wouldn't worry about fixing it until the water heater leaks, then I would have someone competent already vetted to clean it up and do it properly.

    The piping isn't supported or routed in a neat and workperson like manner. The electrical fittings and wiring method don't match. Conduit/flex/armored cable probably should be used for all of the wiring and it also isn't supported. There is no backflow protection for the various relief, vent, and drain lines. The one thing I might do is cap that drain or purge valve by the air handler so it doesn't accidentally get bumped and cause a flood.
    Allous

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