To check for a dirty burner orifice, remove the lower front cover plate and flame shield - this can be hot - and check the overall color of the flame (burner flame not the pilot flame!). Blue is the desired color; orange indicates partially plugged burners and the need for service.

Other potential problems - longshots - are a short cycling thermocouple, or massive sediment buildup insulating the burner from the water. The thermocouple controls flame ignition. It could cause the flame to ignite and then shut down, thus taking more time to reach desired water temperature. It is relatively cheap and easy to change.

If the hot water tank has not had regular flushing, a sediment layer can be produced at the bottom of the tank. Flushing may help this problem, but be prepared to replace the tank, because thoroughly flushing an old, dirty tank can create leaks in the lining.

The exterior insulating blanket won't save enough heat on a modern tank to notice a difference. They are insulated at the factory beneath the metal surface. Usually only older, uninsulated tanks need blankets. In my ever-so-humble opinion I would cut it up and use it on the uninsulated pipes in the crawlspace.

Q: Darrell, you are The Man! Thanks for the article on galvanized pipe. I, too, have constricted, rusting water supply pipes that need replacement. Can I replumb myself? How does one decide how many get replaced, the type of replacement pipe material and how do I know a plumber isn't going to rip me off?

A: I feel your pain. Sometimes I could swear my lawyer and dentist are ripping me off, but they don't charge as much as some plumbers. Of course I didn't get three bids for that last crown either, which is exactly what you should do.

Galvanized pipe gets visibly rusty at the threaded joints first. The constrictions are worst in the horizontal sections, especially the section coming from the street.

Replacement of only some pieces can be difficult when the material has degraded. Rusted joints can break on the next piece downline creating a seemingly never ending task.

Each system is different and every plumber will have a slightly different opinion on what's necessary.

Many times only the horizontal sections in a crawlspace or unfinished basement are replaced and the vertical "stubs" up to each fixture remain. This cuts the cost dramatically and eliminates the need for repair of interior wall surfaces.

Local codes determine the type of piping you can use.

Copper is still the industry standard. A torch, solder and some degree of skill is necessary to install copper.

Galvanized requires a threading tool or pre-threaded pipe lengths and a couple of big wrenches.

CPVC glues together and is relatively simple to work with.

Polybutylene is flexible - good for inaccessible areas. It requires special connection fittings, usually installed as part of a complete system.

Ask The Expert answers readers' questions every Saturday. Send questions to Ask The Expert, Seattle Times, P.O. Box 70, Seattle, WA 98111, or call 206-464-8514 to leave your questions on Ask The Expert's recorded line. E-mail address is dhay@seattletimes.com