4

Hot Water Boiler Reset Control
Hot Water Boiler Reset Control - Richard, We are looking at replacing our boiler with a new hot water boiler. The HVAC contractor, I suppose he is the salesman for the HVAC contractor, is trying to sell us what he refers to as a reset control for our boiler. He tells us it will save us more money by making our boiler more efficient. I think I understand how it works but my wife is not entirely sure about it. Can you tell us what you think about a boiler reset control and how it works?

Thanks and we have learned so much from High Performance HVAC. And keep up the good work.

Brent

Hot Water Boiler Reset Control Answers

Brent,

Thanks for writing to High Performance HVAC and asking a good question. I am certain there is not much information on the internet about boiler reset controls and how they work. The HVAC salesman is correct about this device saving you money. When a salesman states that you really need to look a little deeper and compare the cost of the reset control against your possible savings. Furthermore, it is a basic return on investment question and answer. First, ask him how much money you will save and there are a few factors involved.

First, a reset control will save you money on the amount you pay in energy costs. Whether you have a gas boiler or an oil boiler a reset control will cause your boiler to run less. Furthermore, you need to factor in the maintenance and run-time for the boiler and the amount of reduction in run-time and boiler maintenance because of the reset control. Compare this to running your car less. Consequently, if it sits in the driveway most of the time then the car gets less wear and tear and needs less maintenance and repair it costs you less in the long run.

Hot Water Boiler Reset Control - Questions

The boiler reset control will cause your boiler to run less provided your house is well insulated which is very important to the reduction of heat loss in the wintertime. Ask questions about this and more than likely you will catch the HVAC salesman off guard and he may not have a good answer for you. He should be able to have information from the factory about cost reductions in all the categories I mentioned. If this device saves you money then there should be data available showing the amount of cost reduction. A cost reduction based on certain parameters in a test by the boiler manufacturer, accredited agency or organization that have done such tests.

Hot Water Boiler Reset Control – How a Boiler Reset Controller Works

A boiler reset controller can be either a solid state device or an electrical mechanical device. Basically, it is a switch that opens and closes based on temperature. In solid state controls the boiler reset controller works off a table. Furthermore, an example of a table would look like this:

Outside Ambient Temperature

Outdoor Temperature Sensor Input
  • -20° F
  • -15° F
  • -10° F
  • -5° F
  • 0° F
  • 5° F
  • 10° F
  • 15° F
  • 20° F
  • 25° F
  • 30° F

Boiler Cut-Off

Boiler Set Point Changed To
  • 185° F
  • 180° F
  • 175° F
  • 170° F
  • 165° F
  • 160° F
  • 155° F
  • 153° F
  • 151° F
  • 149° F
  • 147° F

Savings in Reduced Energy Costs

Based on outside air temperature, the boiler reset control will reset the boiler high set point. If it is 0° F. outside the maximum temperature the boiler will produce will be 165° F. This is demand control and it saves you money by causing the boiler to deliver a lesser temperature to the hot water loop because it is unnecessary for the boiler to produce a higher temperature water to satisfy demand or load. Additionally, an electro-mechanical control works nearly the same way and is just as reliable as the solid state control. Furthermore, it doesn’t matter, if the cost of the boiler reset control is reasonable I would buy it for my boiler. That is, if I had a boiler for heating.

Lastly, Brent, good luck to you and I hope your new boiler is efficient and provides your family with many years of comfort and warmth.

Furthermore, for more information about boilers and HVAC click here.

High Performance HVAC Boiler Information

High Performance HVAC

Hot Water Boiler Reset Control

4