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Radiant Heating Problems

What is Radiant Heating?

Unlike other types of heating systems, radiant heating works with heating elements installed in floors, walls and ceiling. The elements heat the surrounding surfaces which then radiate heat into a room. As the air on the room warms and rises, some amount of natural convection occurs without the need for fans or blowers. Read below where Experts have answered a large number of questions regarding radiant heating problems below.

If a Hannel Radiant Floor Heating system was recently repaired and worked for a while, but then then stops circulating the hot water, how would one fix the reoccurring issue?

It could be that there is air in the system. There is a good chance that all the air was not of purged from the system and with use the air bubbles collect in one place and form one big bubble that blocks the flow. It would be a good idea to call the repairman again to purge the system properly.

How would someone set a Viessman/Vitodenz 100 radiant heating system to maintain at 50 degrees while out of the home for a few months during cold weather?

What you need to guard against is a power outage that could cause the boiler’s safety devices to activate and prevent it from restarting when the power returns. Set the thermostat to the minimum temperature you want in your home when you are away. Fit portable electric quartz heater with tip over switches that will activate them if your house get colder than the radiant heat thermostat setting. Use one 1500 watt heater for every 700 sq. ft. and plug each one into a separate circuit. You could also consider adding propylene glycol antifreeze to the CH water loop. Ensure you do not use a poisonous antifreeze like ethylene glycol. Glycol will make the radiant heating system less efficient, but will protect against freezing.

Is it dangerous to have a floor radiant heating system with a Raybak boiler output water temperature of 160 degrees?

The boiler is typically set to run at a high temperature so that there is no exhaust condensation. If the boiler is working okay and 160 degrees is the setting it was installed at that should be a safe temperature. Most radiant heat systems have a mixing valve that reduces the heat of the water at the radiant panels. This is usually 100 to 110 degrees.

My house has an old floor radiant heating system installed in 1947 with a natural gas boiler and cast iron piping in the slab in a continuous loop. It works fine, but I want to know how I can reduce the energy costs.

The best way would be to replace your boiler. A new model condensing gas boiler can be up to 95% efficient, whereas you will be lucky of your old boiler give you 70%. The size of your piping means that the water content will be large so it would be better to oversize the new boiler by about 30%. Be sure that the existing piping is completely cleansed and flushed before installing the new condensing boiler. If you install a 95% boiler you may qualify for Federal tax credit. A cheaper option would be to go in for a modern cast iron block boiler which would be more compatible with your system. It could be around $1,000 cheaper, but will give you an efficiency of around 80% plus.

I have a radiant heating system with an Amitrol WHS80DW hot water maker. I want to replace the upper seal which is leaking. The bolts are rusted and I want to know if they are replaceable or if they are welded to the assembly, in which case I will have problems if they break.

The model you mention has a flange with bolts with nuts, so you will not have a problem if the bolts break. It is usually advisable that you replace the current bolts with stainless steel bolts so that the problem does not resurface in the future.

Radiant heating systems are a very effective way to heat a home. But because of the complexity of the piping and installation of the heating panels care must the taken when tackling radiant heating problems. Follow the troubleshooting instructions given in your owner’s manual and if the issue you are facing is not covered there or if it does not solve your problem, it is best to get the help of an Expert to resolve the issue.
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