Homeowner: I wish I never bought this boiler! Contractor: I wish I never took this job! How could a perfectly engineered job wind up with this conversation? Sadly, this conversation takes place more often than it should. The worst part is the job can be installed perfectly and the homeowner is still dissatisfied.

Contractors often fall into the trap of finding the job, selling the job, doing the job, collecting for the job — wash, rinse, repeat. A key factor many quality contractors overlook is educating the homeowner about the proposed system, available options and expected performance.

Let’s discuss some key areas where you may experience unhappy customers if expectations are not managed prior to installation. The following scenarios illustrate how easily a good job can turn contentious even when proper design and installation procedures are followed:

Conversation one

A homeowner is replacing a 30-year-old cast-iron oil boiler with a domestic coil and cast-iron radiators. She was very happy with the performance, but is concerned about conserving fuel. After watching a home improvement episode on efficiency, she had a setback thermostat installed and noticed a small savings.

Meanwhile, a natural gas line has recently been run through the neighborhood. Her contractor suggests a high-efficiency gas boiler. They explain the increased efficiency benefits, the extra available space when the oil tank is removed and the quiet operation. The homeowner is thrilled and signs the contract immediately. They perform a heat loss calculation and install the properly sized boiler with the supplied outdoor reset.

Flash forward to winter. The contractor gets a call that the boiler is not working. The homeowner states she is extremely unhappy. The radiators are always cold! The contractor checks the thermostat, which is set for 70 degrees. The indoor temperature is 70 degrees.

The technician, bewildered, asks what she is unhappy with. The radiators used to get so hot she couldn’t touch them. They barely get warm now! And another thing — the setback thermostat used to work great. Now the house takes much longer to warm up.

The technician, who has eight more calls to get to and is short on diplomacy after a string of 70-hour workweeks, says, “I don’t know. That’s the way they work.” How will this conversation end? See the opening of this article for a guess.

How do we avoid these conversations? Education! The homeowner may have been aware of all the benefits of the new system, but not what other dynamics the system would include.

In this, we are concerned with maintaining room set point, not radiator temperature. In her mind, however, if the thermostat is calling for heat, beginning at 60-degree outdoor temperatures, the radiators should be approximately the same temperature as the core of the sun.

If she was made aware of all the money that stayed in her pocket rather than flying out of the vent, she likely would have processed this experience much differently. Removing outdoor reset is not a responsible solution, as doing so negatively impacts a condensing boiler’s efficiency.

Conversation to have: Some cast-iron boilers operate in on/off (cold start) mode, while others may maintain a temperature of 140-160 degrees with a high limit of 180-200 degrees. They also may have 10-15 times the water volume of a condensing boiler. This can result in heat loss up the chimney. Newer water tube condensing boilers can have less than 1 gallon of water in the heat exchanger, and they do not maintain a minimum boiler temperature. They also modulate to match changing load requirements.

Setback schedules and expectations should be managed accordingly, as recovery when using a night setback may take longer due to decreased water volume. Night setback spread is often reduced or eliminated entirely. 

Alternatively, the occupied temperature on time can be set earlier to compensate for the additional time required to bring the house back up to temperature.

Conversation two

Another episode of a home renovation series showcased a combi boiler. The homeowner in this case was intrigued, hearing the boiler had zero standby losses. Being concerned about his monthly home expenses as well as the environment, he thought this sounded like a great idea.

The existing system included a cast-iron boiler and a 40-gallon hot water heater, both running on gas. The house was a moderately sized ranch with a single bathroom at one end.

He contacted a local company with stellar reviews. The sales associate helped the owner appreciate the truckloads of money he could save with a condensing combi system, and that for a single-bathroom home the combi was the perfect fit.

Combined with an energy conservation incentive loan, the homeowner thought he couldn’t afford not to install a new boiler. An appropriate load calculation was done, and the boiler was installed exactly to manufacturer’s specifications.

Then, the morning after the installation, the contractor received a call from what could politely be called a contentious homeowner.

“I thought you said this boiler could provide hot water all day long if the capacity wasn’t exceeded. I got in the shower and had plenty of hot water. My wife got in next and — well, here, you talk to her.”

The homeowner explains through clenched teeth that she got in the shower and had 30 seconds of hot water, then was doused with 45-degree water in the face.

The office manager for the installer politely tries to explain the phenomenon of the sandwich effect, with the only “effect” being to fan the flames of venomous rage.

To appease the homeowner, an uninsulated recirculating loop was installed. Six months later, the homeowner calls back.

“This boiler is a lemon. The loop you installed didn’t solve the problem and now we have no hot water!”

The on-call technician rushes over and finds the boiler has a failed blower. Surprised, he checks the boiler cycles and run time and sees the boiler has an average run time of 45 seconds — and the cycle count is appropriate for a boiler that is 6 years old, not 6 months. Again, see the opening statements for a G-rated recap of the resulting conversation.

Conversation to have: With many combi boilers there is no domestic hot water storage. The sandwich effect occurs when a fixture is opened, the pipe feeding the fixture is filled with hot water and then the fixture is closed. If someone reopens the fixture shortly after initial usage, hot water will be present almost immediately. However, cold water will be flowing into the boiler as it progresses through its start-up sequence.

This is how the homeowner got a splash of cold water after entering the shower. This phenomenon is made worse on long runs of potable water pipe, like a ranch with the boiler at one end and the bathroom at the other. 

Additionally, when used in conjunction with high-efficiency dishwashers or clothes washing machines, hot water may not be present at the fixture before the appliance is full, supplying cold water when the appliance is looking for only hot.

Installing a recirculation loop helps with this issue, but should be approached with caution. Domestic hot water recirculation systems should be designed for efficiency, comfort and with the operating characteristics of the boiler in mind. They can increase cycles and in extreme cases elevate cycle rates to the point that component failure can result. Recirculation design is important enough that it will be covered in a future article.

An appropriately sized buffer tank will resolve the problem, but at that point why not just install a heating boiler and indirect storage tank? Some manufacturers incorporate small buffer tanks in the boiler to address this issue. Combi boilers perform very well when installed in appropriate applications and when the end-user is properly educated about what they can expect.

Any occupation where one is engaging with an uninformed or misinformed public can be challenging. With a sea of misinformation available at customers’ fingertips, the problem grows worse.

When it involves a prospective client’s home comfort, it becomes critical that contractors take a few minutes before the project to educate homeowners about what to expect after the installation is complete. And as always, the adage applies: “Under promise and over-perform! 

Dan Rettig’s career began as an HVAC commercial service technician focusing on chillers, cooling towers, heat pumps, boilers and oil burners. He also has experience with multiple control platforms for building integration. Over the last 13 years, Rettig has been employed by two different boiler manufacturers, including 12 years of product management experience. Rettig is currently the product manager for Thermal Solutions, a subsidiary of Heating Solutions Sales Co.