Hi everybody. I’m a homeowner looking for some advice about replacing a boiler and how best to handle my poor water quality. This is my first house with a boiler, gas heating and a radiant heating system so I’m in serious need of good information from the experienced installers, home owners and manufacturer representatives here.
Background: I bought my house 2 years ago (near Santa Fe, NM). It has a 13 year old cast iron boiler and separate water heater (both propane). No water softener. And a radiant heating system under a brick floor. There’s also a wood burning stove that serves to heat most of the house. The radiant floor runs throughout the house but only two of the rooms routinely command heat. Anyway, the boiler is having issues (flame rollout) and I have asked a few local HVAC companies to give me estimates to replace it and the water heater.
The well water quality is poor. Test results from when I bought the house include:
Total Hardness: 454 mg/L (454 ppm or 27 grains per gallon)
Total dissolved Solids: 283 mg/L (283 ppm or 17 grains per gallon)
Manganese: 0.0025 mg/L
Iron: not detected
Here’s what I think based on what I’ve been reading. Let me know what I got right, wrong or simply your recommendation:
Water Quality: My water is pretty aggressive so anything I can do to make to better is probably money well spent. Things like using a system cleaner and then flushing the old system when they remove the old boiler to flush out debris that’s already in there. Install micro bubble air remover and a dirt separator (magnetic?) to continuously remove air and debris from the system. And add corrosion inhibitors to the new water to prevent rust and keep the calcium carbonate in solution. Then to avoid introducing air and more hard water to the system, once it’s up and running I should not open it up again unless it’s needed for a service repair.
Boilers: Regardless of these steps, I should probably avoid the high efficiency boilers because my water is pretty aggressive and significant scaling will likely develop over time and these have small tubing and thinner metal components which are more easily damaged. The scaling will reduce the efficiency, probably require additional servicing throughout its lifetime, void the warranty with respect to scaling damage, and greatly shorten the lifetime of the boiler. Instead, I should be looking for a traditional cast iron boiler because they have wider pipes and are more tolerant of the scaling that will develop. I won’t see super high efficiency or a 25 year life but I probably wasn’t going to see those with a high efficiency unit either. And there is less to break down and require maintenance (I live an hour from Santa Fe so service calls are expensive).
Water Heater: I’m thinking of replacing it with another stand-alone, water heater. The poor water quality suggest I don’t get a tankless, high efficiency one. And I’ve seen some discussions about indirect heating where the boiler supplies the heat for the water heater but it’s not obvious to me that this would be a better approach. The boiler would have to run all year instead of just in the summer and if the boiler is down for repairs then I’ve also lost my hot water (which is a bigger deal than the boiler because of the wood burning stove).
Water Softeners: I’m uncertain about the use of a water softener to treat the water. I’ve read many articles that say one should be added if you have hard water to prevent scaling in both the boiler and the water heat. However, an HVAC representative that came out to my house to prepare an estimate, told me that I only needed to add one if I wanted to put in a high efficiency unit and that it wasn’t necessary for a cast iron boiler. Meanwhile the Slant Fin web site says absolutely do NOT use a water softener. They argue that that is “old school thinking” and that softened water has had the natural mineral balance disturbed and “will try to re-balance itself by leaching the required minerals from the metals back into the water; this leaching of minerals will cause a higher rate of corrosion”. Instead they say you should use corrosion inhibitors because they have dispersants that combat the precipitation of calcium carbonate. They also say water with a hardness above 11.7 gpg can lead to scale build up, even with the use of corrosion inhibitors, and should not be used.
As a side note, I would rather not add the water softener simply because it’s going to flush a lot of water into my septic system. My previous house had one and it ran its regeneration cycle ever other day or so. The water in my new house is much, much harder so I have to think a water softener is going to have to run its regeneration cycle much more frequently. That might introduce a new problem with the septic system. Especially during monsoon season.
Am I on the right track with any of this?
Contractors: If you’ve worked with a HVAC installer in Santa Fe that you want to recommend, by all means let me know. I understand picking a good installer is at least half the battle. But I’m new to the area so I don’t have much history with any of them. I’m relying on Angie’s List and Google reviews for insight into their work. And a little common sense.
So far one HVAC company come out to the house, inspected the boiler/water heater, took measurements for a heat load calculation, asked for a couple of my water test, took a water sample, and said they would get me an estimate in a few days. Another company said they could save me money but not coming out and instead asked me to email them pictures of my boiler/water heater. They obviously didn't do a heat load calculation, didn't ask about the water quality and they emailed me an estimate the next day. I assume they sized the boiler based on the existing unit. A third company will be coming out later this week.
If you made it this far, thanks for taking the time to read my post. Again, any feedback, recommendations, etc. would be appreciated.