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Mod/con boiler flat panel radiators questions
Hello
After much deliberation, I will be replacing my poorly functioning heating and cooling systems at the same time as getting a kitchen addition to my home. Currently have oil steam boiler with cast iron radiators and a high velocity spacepak system for cooling. Home is about 100 years old but has had spray foam put in the walls and closed foam in the attic and double pane windows. A blower door test with thermal imaging was performed and exposed some areas bringing in cold air. A “short basement” type crawl space will get close cell spray foamed and the house will get some air sealing improvements. Also the home is climate 4A lower Hudson valley NY
The current plan is to remove everything (cast iron boiler, steam pipes, radiators, spacepak air handler, outdoor condenser, duct work. The second floor will get a ducted Mitsubishi hyper heat pump (the bedrooms are small and we really need to reclaim the radiator space for beds and what not). The first floor will get 3 ductless units for cooling and shoulder season heating. There will be a gas conversion and new has boiler for hydronic heating during winter. New pex lines, manifold, etc. The new 400 or so square foot kitchen will have radiant flooring under porcelain tile. This is where I need advice. I am deciding between cast iron radiators or modern flat panel radiators for the remaining first floor to replace all the steam radiators. This decision would also help with the decision to have a cast iron boiler or mod con boiler. I do like the idea of lower temp radiators so I could use a mod con boiler and get greater gas efficiency. Also it would allow me one day to convert to an air to water heat pump when they are more mainstream. If I went with cast iron radiator and cast iron boiler and had my temps at 160-180 i could never reuse it with heat pump. I know cast iron radiators would be easier to be more comfortable and that’s why I’m trying to make my home higher performing with insulation and air sealing to allow lower temp radiators to be a viable option in my old home.
After much deliberation, I will be replacing my poorly functioning heating and cooling systems at the same time as getting a kitchen addition to my home. Currently have oil steam boiler with cast iron radiators and a high velocity spacepak system for cooling. Home is about 100 years old but has had spray foam put in the walls and closed foam in the attic and double pane windows. A blower door test with thermal imaging was performed and exposed some areas bringing in cold air. A “short basement” type crawl space will get close cell spray foamed and the house will get some air sealing improvements. Also the home is climate 4A lower Hudson valley NY
The current plan is to remove everything (cast iron boiler, steam pipes, radiators, spacepak air handler, outdoor condenser, duct work. The second floor will get a ducted Mitsubishi hyper heat pump (the bedrooms are small and we really need to reclaim the radiator space for beds and what not). The first floor will get 3 ductless units for cooling and shoulder season heating. There will be a gas conversion and new has boiler for hydronic heating during winter. New pex lines, manifold, etc. The new 400 or so square foot kitchen will have radiant flooring under porcelain tile. This is where I need advice. I am deciding between cast iron radiators or modern flat panel radiators for the remaining first floor to replace all the steam radiators. This decision would also help with the decision to have a cast iron boiler or mod con boiler. I do like the idea of lower temp radiators so I could use a mod con boiler and get greater gas efficiency. Also it would allow me one day to convert to an air to water heat pump when they are more mainstream. If I went with cast iron radiator and cast iron boiler and had my temps at 160-180 i could never reuse it with heat pump. I know cast iron radiators would be easier to be more comfortable and that’s why I’m trying to make my home higher performing with insulation and air sealing to allow lower temp radiators to be a viable option in my old home.
What would you all do?!
bombaloo
1
Re: Do I need to have this redone? Should I? Attic Installation LG Low Static Ducted Heat Pump
is that .7 wc or .07. That is going to make a huge difference
pedmec
1
Re: Do I need to have this redone? Should I? Attic Installation LG Low Static Ducted Heat Pump
And there Wrong!
Just updating. They came back today and this is what they found. .29 on the supply. .7 on the return combined .36 in wg.
Tech insisted that combined equals .22 (29-7) not .36 (29+7). I insisted that for "Maximum External Static Pressure" the relevant number is .36 in wg. He called someone else who confirmed his POV but he is going to ask someone else and look into it further. Furthermore, he doesn't think the external static pressure matters. He says the air flow CFMs are good and that is what they and thousands of people design around, not static pressure. I am working on this still... I just wanted to give an update for people who have been helping me. I am still working on this...
https://calcerts.zendesk.com/hc/en-us/articles/360051851293-Total-External-Static-Pressure-07-15-2020
https://hvacrschool.com/total-external-static-pressure-tesp-a-basic-review/
pecmsg
2
Re: Need Help Understanding Dielectrics
Hi, There is a lot to this, but a simple answer is that oxygen plays a big role in making the corrosion/rusting happen. In the closed boiler system, there is little oxygen. In the open domestic hot water system, there is lots of oxygen. My preferred way to hook up a water heater is to use a plastic lined nipple at the tank and then a corrugated stainless or copper flex connector above that. I only use flexes that have true dielectrics built into the ends. The true dielectrics look like the attached photo, with plastic between the flex line metal and the nut. 
This approach puts distance between different metals and does not expose any poorly protected steel to the water. I avoid using standard steel dielectric unions as they often cause trouble down the line.
Yours, Larry
This approach puts distance between different metals and does not expose any poorly protected steel to the water. I avoid using standard steel dielectric unions as they often cause trouble down the line. Yours, Larry
Re: Importance of outdoor temp sensor for reset on Viessmann Vitodens B1KE-120 ?
Tekmar, now a Watts company pioneered outdoor reset controls, sold thousands. Now most boilers have this option built in
Their essays are still some of the best at explaining reset functions
Their essays are still some of the best at explaining reset functions
hot_rod
2
Re: Importance of outdoor temp sensor for reset on Viessmann Vitodens B1KE-120 ?
I think you're mixing up your min flow rate for your domestic hot, 0.5 gpm, and the low loss header that you likely should have for the heating flow,... generally these are meant to be piped primary/secondary. If the flow rates are acceptable for the boiler they can be direct piped, but generally not a great idea.Can you elaborate on flow rates being acceptable? I'm fairly certain that I'm never going to exceed the max flow rate, but I have faucets that don't often support much flow. What will happen if i regularly use a faucet below the minimum flow rate? I see the B1KE-120 lists 0.5 gpm as the minimum flow through the heat exchanger for boiler start. Does that mean that 0.5 gpm is the minimal flow? If I use less then 0.5 gpm will it just never produce hot water? And if I'm using 0.6 gpm and it gets reduced to 0.4 gpm the hot water will cease to come out?
My main concern would be that I was doing damage to the boiler so hopefully that's not the case. Maybe it cycles a few additional times leading to a bit more energy use and wear?
edit: I just checked my bathroom faucet and it's only about .3 gpm currently
It clearly needs a new aerator, despite the current one being less than a year old. Mineral deposits tend to build up over time. I cleaned it a bit and got the flow above 0.5 gpm.
I found this quote:
"A low-loss header must be used when the system flow rate exceeds the maximum (or minimum) flow rate of the Vitodens 100-W boiler"
I'm guessing I don't have a "low-loss header"...
the domestic, and the aerator you just cleaned,
if the 0.3 was you only hot domestic call, the boiler heater would not have turned on, or stayed on if it did turn on, now with the clean aerator flow at or above0.5, the boiler will send hot water.
the low loss header, or primary secondary piping, allows for required heating flow thru the boiler, if and when a too small flow rate zone is calling for heat.
2 different issues wrapped up inside you wall heater.
neilc
1
Re: Venting - What's code?
As far as I know, there is no difference on the residential side anyway. I have always plumbed two story houses using the aggregate area, and generally wind up with one three inch vent through the roof, but not necessarily all the way to the main.
Rick
Rick
Re: Venting - What's code?
When I was in Alaska, you could have multiple penetrations coming out the roof as long as the aggregate area equaled the required building sewer line, usually 3", and they had to be a minimum of 2" because of frost. I always tried to tie all my lines in in the attic so I only had one penetration through the roof, which I made as close to the peak as I could.
Rick
Rick
Re: Hydrostat 3250 Plus issues
Take a picture of the hydrostat with the cover off so your settings can be viewed.
pedmec
1
