People will often have a their cast iron boilers replaced with 90% efficiency boilers to save money . When these boilers are being installed you MUST follow the manufactures recommendations for piping methods and pump placement. These are extremely important to follow strenuously or else many other problems could arise. A lot of these problems may not be noticed or show up for up to 3 years. Which often times will be as the warranty expires. The problem with these issues is when they occur they often are confused with normal problems. Such as; Temperature and pressure relief valves (TNP’s) , Expansion Tanks, Fill Valves, Zone Valves and Air Separators.
When these problems are fixed they will keep rearing their head and will start to cost a lot of money. It may seem as if this issue will never go away. This is when you need to have a skilled boiler technician come in and take an extensive look at your system. The technician needs to be looking at all variables of your system. Starting from the very beginning.
First the technician will need to make sure that your boiler is properly sized for your home. This is extremely important because if your boiler is undersized it will not properly supply your home on a day when every zone is calling (all rooms need heat). And if your boiler is over sized you will be dealing with boiler short cycling (turning off without reaching peak efficiency) when there aren’t enough zones calling. When your boiler is over sized you also risk over heating rooms, because your boiler is then heating up the water too quickly and not able to properly monitor the temperature of water it is sending to your zones.
The next variable to look at is your how the boiler is piped and if it is to manufacturers recommendations. This is one of the problems that goes unnoticed by many installers and technicians. This is important because if its not piped correctly your hot water may be mixing before serving the zones which will cut your efficiency down and in some cases in half. Sometimes this can be pricey to fix, but this is extremely important and worth the investment. Because if your boiler is running at max efficiency you will save more money each year on your utilities. Therefore you will get a return on your investment to re pipe your system.
The other very important part of your system are your pumps. If your pumps are in the improper location they will not properly serve your zones. Often times if your pump is placed incorrectly. The water will take the path of least resistance and can mix with cold water therefore crushing your efficiency or the water may push back to your boiler and overheat your heat exchanger causing it error out on high limit. When your boiler codes out on high limit this will make it so your heating or domestic needs are not met. This can go unnoticed in heating and DHW (Domestic Hot Water) often because if you have a really big zone calling. The Boiler still be distributing enough water so that your boiler will not error on high limit. When you have a call for a smaller zone it will then create that issue. When your boiler is supplying a DHW tank this can go unnoticed because you will still have the hot water you need and your tank will still be satisfied but not in the most efficient way possible.
The problems previously mentioned will sometimes take months or even years for the problem to go noticed. Making them very confusing and frustrating for the customer and also the technician. This is something that can be very hard to explain to a customer and often times ends up being blamed on a technician. Even when the original installer can be to blame. Hydronic systems can be very tricky to dial in once installed improperly.